Abstract:
A system for load control in an electrical power system is described, wherein one or more load-control devices are provided to control power delivered to electrical equipment. A remote power authority, such as a power company, government agency, or power transmission company sends one or more commands to the load-control devices to adjust loading on the electrical power system. In one embodiment, the power authority sends shutdown commands. In one embodiment, the power authority sends commands to tell the electric power device to operate in a relatively low-power mode. In one embodiment, the commands are time-limited, thereby allowing the electric power device system to resume normal operation after a specified period of time. In one embodiment, the commands include query commands to cause the control device to report operating characteristics (e.g., efficiency, time of operation, etc.) back to the power authority.

Description:
REFERENCE TO RELATED APPLICATION  
     BACKGROUND  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to systems for reducing load on an electric power system to avoid brownouts and blackouts.  
         [0003]     2. Description of the Related Art  
         [0004]     The increasing demand for electrical energy often produces overload conditions on many electric power distribution systems, particularly during periods of extreme temperatures when consumers are calling for high levels of energy to satisfy their cooling needs. When the customers&#39; demand for energy reaches a given high level, communities are forced to endure rolling blackouts.  
         [0005]     Severe power shortages increase the risk of damage to electrical and electronic equipment. Brownouts can occur at times of extremely high power consumption or power shortages when electric utilities reduce the voltage supply to conserve energy. Brownouts can cause computer resets, memory loss, data loss, and in some cases, overheat electronic equipment components. Motors (e.g., fan motors and air-conditioner compressor motors compressors) can also overheat and burn out. Blackouts are sustained power interruptions caused by overloads, storms, accidents, malfunctions of utility equipment, or other factors. Longer-term power outages can last from hours to days.  
         [0006]     At present, the typical procedure often used to prevent brownouts and widespread blackouts is to institute rolling blackouts. Rolling blackouts reduce the stress on the electrical power grid, but they are very disruptive to businesses and personal lives. Electrical and electronic equipment is often damaged after a utility brownout or blackout when the power is turned back on and a burst of electricity surges through the lines. Equipment can fail because of a sudden lack of power, lower voltage levels, power surges when service is restored.  
       SUMMARY  
       [0007]     These and other problems are solved by a system for load control in an electrical power system where one or more load-control devices are provided to reduce system load by selectively shutting down relatively high-load equipment such, as, for example, air-conditioning systems, a refrigeration systems, a pool pump systems, electric ovens, and the like. The load control devices are configured to receive commands for controlling the relatively high-load system. A power authority, such as a power utility, governmental agency, power transmission company, and/or authorized agent of any such bodies, sends one or more commands to the data interfaced devices to adjust loading on the electrical power system. The ability to remotely shut down electrical equipment allows the power authority to provide an orderly reduction of power usage. Power surges can be avoided because the remote shutdown facility can schedule a staggered restart of the controlled equipment. The power load can be reduced in an intelligent manner that minimizes the impact on businesses and personal lives. In one embodiment, power usage is reduced by first shutting down relatively less important equipment, such as, for example, pool filter pumps, hot water heaters, electric ovens, etc. If further reduction in load is required, the system can also shut down relatively more important equipment such as, for example, refrigerators, air-conditioners, and the like on a rolling basis. Relatively less important equipment (and other equipment that can be run during the night or other low-load periods) such as pool filter pumps can be shut down for extended periods of time.  
         [0008]     In one embodiment, the system shuts down electrical equipment devices according to a device type (e.g., pool pump, oven, hot water heater, air-conditioner, etc.). In one embodiment, the system shuts down electrical equipment by device type in an order that corresponds to the relative importance of the device. In one embodiment, the system shuts down electrical equipment for a selected period of time. In one embodiment, the time period varies according to the type of device. In one embodiment, relatively less important devices are shut down for longer periods than relatively more important device.  
         [0009]     In one embodiment, the system sends commands to instruct electrical devices to operate in a low-power mode (or high-efficiency mode) before sending a full shutdown commands.  
         [0010]     In one embodiment, the power authority sends shutdown commands. In one embodiment, the power authority sends commands to instruct the high-load system to operate in a relatively low-power mode. In one embodiment, the commands are time-limited, thereby allowing the electrical equipment to resume normal operation after a specified period of time. In one embodiment, the commands include query commands to cause the high-load system to report operating characteristics (e.g., efficiency, time of operation, etc.) back to the power authority.  
         [0011]     In one embodiment, the system sends shutdown and startup commands. In one embodiment, the system sends shutdown commands that instruct electrical equipment to shut down for a specified period of time. In one embodiment, the shutdown time is randomized to reduce power surges when equipment restarts.  
         [0012]     In one embodiment, power line data transmission (also referred to as current-carrier transmission) is used to send commands, (e.g., shutdown commands, startup commands, etc.). In one embodiment, a signal injector injects power line data transmission signals onto a power line.  
         [0013]     In one embodiment,a signal injector is provided at a transformer and when loading on the transformer becomes too high, the signal injector sends commands to shut down selected equipment downstream of the transformer in order to reduce the load on the transformer.  
         [0014]     In one embodiment, a load-control device controls power to a relatively high-load device. In one embodiment, a load-control and power-monitoring device controls power to a relatively high-load device and monitors power provided to the device. In one embodiment, a load-control device controls a relatively high-load device using relatively low power control, such as, for example, thermostat control lines. In one embodiment, a load-control and power-monitoring device controls power to a relatively high-load device and monitors current on multiple phases. In one embodiment, a load-control and power-monitoring device controls power to a relatively high-load device and that provides circuit breaker overload protection. In one embodiment, a load-control and power-monitoring device controls power to a relatively high-load device and provides circuit breaker overload protection with electric trip. In one embodiment, a single-phase load-control and power-monitoring device controls power to a relatively high-load device.  
         [0015]     In one embodiment, a display system provides monitoring of electrical devices and/or displays messages from a power authority.  
         [0016]     In one embodiment, a power meter provides load control capability. In one embodiment, a load control module is configured for use in connection with a standard power meter.  
         [0017]     In one embodiment, an electric distribution system provides with automatic downstream load control. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  shows a power distribution system for a home or commercial structure.  
         [0019]      FIG. 2A  shows a power distribution system for a home or commercial structure wherein an injector provides power line communications.  
         [0020]      FIG. 2B  shows a power distribution system for a home or commercial structure wherein load-control modules are provided to allow the power authority to shed power system loads by remotely switching off certain electrical equipment.  
         [0021]      FIG. 3  shows a load-control device that controls power to a relatively high-load device.  
         [0022]      FIG. 4  shows a load-control and power-monitoring device that controls power to a relatively high-load device.  
         [0023]      FIG. 5  shows a load-control device for controlling a relatively high-load device using relatively low power control, such as, for example, thermostat control lines.  
         [0024]      FIG. 6  shows a display system for monitoring electrical devices and/or for receiving messages from a power authority.  
         [0025]      FIG. 7  shows a load-control and power-monitoring device that controls power to a relatively high-load device and monitors current on multiple phases.  
         [0026]      FIG. 8  shows a load-control and power-monitoring device that controls power to a relatively high-load device and that provides circuit breaker overload protection.  
         [0027]      FIG. 9  shows a load-control and power-monitoring device that controls power to a relatively high-load device and that provides circuit breaker overload protection with electric trip.  
         [0028]      FIG. 10  shows a single-phase load-control and power-monitoring device that controls power to a relatively high-load device.  
         [0029]      FIG. 11  shows a conventional power meter.  
         [0030]      FIG. 12  shows a power meter with load control capability.  
         [0031]      FIG. 13  shows a load control module for use in connection with a standard power meter.  
         [0032]      FIG. 14  shows an electric distribution system with automatic downstream load control. 
     
    
     DETAILED DESCRIPTION  
       [0033]      FIG. 1  shows an electrical system  100  for a home or commercial structure. In the system  100 , electrical power from a distribution system  101  is provided to a power meter  102 . The power meter  102  measures electrical power provided to a distribution panel  103 . In the distribution panel  103 , power from the meter  102  is provided to a master circuit breaker  104 . Electrical power from the master circuit breaker  104  is provided to various branch circuit breakers  110 -  115 . The branch circuit breakers  110 - 115  provide electric power to various branch circuits in the home or commercial structure. It is common practice to provide a dedicated branch circuit breaker to relatively high-load devices, such as, for example, electric dryers, electric ovens, electric ranges, electric water heaters, electric furnaces, building air-conditioners, pool filter pumps, etc. Thus, for example, in  FIG. 1 , the breaker  112  provides electrical power to a furnace/evaporator/air-handler unit, the breaker  113  provides power to an electric oven  123 , the breaker  114  provides power to a pool filter pump  124 , and the breaker  115  provides power to an air-conditioner condenser unit  125 . The relatively high-load devices on dedicated circuit breakers are typically devices that operate at higher voltage (e.g., on 220 volts in the U.S.) and thus the dedicated circuit breakers  112 - 115  are typically double-pole breakers that switch both “hot” lines in a split-phase system.  
         [0034]     The breaker  110  provides electrical power to a string of electrical outlets  131 - 132 . It is also common practice to provide a single branch circuit breaker to a plurality of electrical outlets for powering relatively low-load electrical devices (e.g., computers, window air-conditioners, refrigerators, lights, entertainment systems, etc.). Thus, for example,  FIG. 1  shows a refrigerator  141  plugged into the electrical outlet  131  and a window air-conditioner unit plugged into the electrical outlet  132 .  
         [0035]     The individual electric power provided to the relatively high-load devices connected to dedicated breakers can be controlled at the relatively high-load device and/or at the dedicated breaker. The individual electric power provided to the relatively low-load devices connected to electrical outlets can be controlled at the outlet and/or in the relatively low-load device. It is typically not practical to control power to the relatively low-load devices at a breaker that serves more than one device.  
         [0036]      FIG. 2A  shows a power distribution system  200  for a home or commercial structure wherein an injector  201  provides power line communications. The injector  201  inserts modulated data signals onto the power line at frequencies other than the 60 Hz (or 50 Hz) frequency used by the power line. In broadband applications, such as, for example, Broadband Power Line (BPL) communications, the data signals are modulated onto carriers in the megahertz range and higher. In medium-bandwidth systems, the carrier frequencies are in the band between approximately a kilohertz range and a megahertz. In relatively low-bandwidth systems, the carriers operate at frequencies below a kilohertz. The relatively high-bandwidth, medium bandwidth, and relatively low-bandwidth systems can typically operate simultaneously without interfering with one another as long as the frequency ranges used by the systems do not overlap. Thus, for example, BPL can typically operate in the presence of a medium-bandwidth system that uses carriers in the frequencies below those used by BPL. Similarly, the medium bandwidth system can typically operate in the presence of a low-bandwidth system that uses frequencies below those used by the medium-bandwidth system.  
         [0037]      FIG. 2B  shows a power distribution system for a home or commercial structure wherein load-control modules  250  are provided to allow the power authority to shed power system loads by remotely switching off certain electrical equipment. The power authority can send commands to the load control modules to shut off electrical equipment by type and/or by identification number. Embodiments of the load-control modules are described in connection with  FIGS. 3-5  and  7 - 10 . In one embodiment, a load monitoring module  251  is provided to monitor and control power provided to the distribution box  103 .  
         [0038]      FIG. 3  shows a load-control device  300  that controls power to a relatively high-load device. In the device  300 , electrical power inputs  320 ,  321  are provided to a modem  301 , to a power supply  302 , and to a power relay  309 . Data from the modem is provided to a processing system  304  that includes a memory  305 . In one embodiment, the memory  305  is a non-volatile memory. An optional programming interface  306  (also known as a data interface) is provided to the processing system  304 . An optional Radio Frequency (RF) transceiver  307  (having an antenna  308 ) is provided to the processing system  304 . The modem  301 , the programming interface  306 , and the transceiver  307  provide data interfaces to the processing system  304 .  
         [0039]     Although referred to herein as a transceiver, when one-way communication is desired, the transceiver  307  can be configured as a receiver for a receive-only system, or a transmitter for a transmit-only system. When configured as a receive-only system, the transceiver  307  can be used to receive instructions from the power authority. When configured as a transmit-only system, the transceiver  307  can be used to send data and/or status information to the power authority. When configured as a transmit/receive system for two-way communication, the transceiver  307  can be used to receive instructions from the power authority and to send data and/or status information to the power authority.  
         [0040]     A control output from the processing system  304  is provided to a control input of the power relay  309 . In one embodiment, the power relay  309  includes a solid-state relay. In one embodiment, the power relay  309  includes a solid-state relay using high-power solid state devices (e.g., triacs, Insulated Gate Bipolar Transistors, Power MOSFETS, etc.). In one embodiment, the power relay  309  includes a mechanical relay. In one embodiment, the power relay  309  is part of a circuit-breaker mechanism that allows the circuit breaker to be switched on and off electrically. In one embodiment, the relay  309  is configured as a double-pole relay that switches the connection between the input terminal  320  and the output terminal  330  as well as the connection between the input terminal  321  and the output terminal  331 . In one embodiment, the input terminal  321  is provided to the output terminal  331  and the relay  309  is configured as a single-pole relay that switches the connection between the input terminal  320  and the output terminal  330 . In one embodiment, the load-control device is configured as a replacement for a double-pole circuit breaker.  
         [0041]     In one embodiment, the modem  301  facilitates one-way communication, to allow the processing system  304  to receive instructions and/or data from the injector  201  or other power line communication device. In one embodiment, the modem  301  facilitates two-way communication, to allow the processing system  304  to receive instructions and/or data from the injector  201  or other power line communication device and to send data to the injector  201  or to other power line communication devices.  
         [0042]     The optional programming interface  306  can be configured as a computer port, such as, for example, a Universal Serial Bus (USB) port, a firewire port, an Ethernet port, a serial port, etc. In one embodiment, connection to the programming interface is  306  is provided by an external connector. In one embodiment, connection to the programming interface is provided by a magnetic coupling, a capacitive coupling, and/or an optical coupling (e.g., an InfraRed (IR) coupling, a visible light coupling, a fiber optic connector, a visible light coupling, etc.). The optional programming interface  306  can be configured to provide program code, identification codes, configuration codes, etc. to the programming system  304  and/or to read data (e.g., programming code, identification codes, configuration data, diagnostic data, log file data, etc.) from the programming system  304 .  
         [0043]     The optional RF transceiver  307  can be configured to provide communication with the processing system  304  through standard wireless computer networking systems, such as, for example, IEEE 802.11, bluetooth, etc. The optional RF transceiver  307  can be configured to provide communication with the processing system  304  through proprietary wireless protocols using frequencies in the HF, UHF, VHF, and/or microwave bands. The optional RF transceiver  307  can be configured to provide communication using cellular telephone systems, pager systems, on subcarriers of FM or AM radio stations, satellite communications, etc. with the processing system  304  through proprietary wireless protocols using frequencies in the HF, UHF, VHF, and/or microwave bands. In one embodiment, the antenna  308  is electromagnetically coupled to one or more electric circuits wires (such as for example, the power input lines  320  or  321 , or other nearby electrical power circuits) so that the power circuits can operate as an antenna.  
         [0044]     The modem  301  receives modulated power line data signals from the power inputs  320 ,  321 , demodulates the signals, and provides the data to the processing system  304 . The processing system  304  controls the relay  309  to provide power to the output lines  330 ,  331 . The output lines  330 ,  331  are provided to the electrical equipment controlled by the load-control device  300 .  
         [0045]     In one embodiment, the programming system  304  uses the memory  305  to keep a log file recording commands received and/or actions taken (e.g., when the relay  309  was turned on and off, how long the relay  309 , was off, etc.). In one embodiment, the programming interface  306  can be used to read the log file. In one embodiment, the log file can be read using the modem  301 . In one embodiment, the log file can be read using the RF transceiver  307 . In one embodiment, data from the log file can be read using an Automatic Meter Reading (AMR) system. In one embodiment, an AMR system interfaces with the processing system  304  via the modem  301 , the programming interface  306  and/or the transceiver  307 .  
         [0046]     In one embodiment, fraudulent use, malfunctions, and/or bypassing of the load-control device is detected, at least in part, by reviewing the log file stored in the memory  305 . The power authority knows when shutdown instructions were issued to each load-control device. By comparing the known shutdown instructions with the data in the log file, the power authority can determine whether the load-control device shut down the electrical equipment as instructed.  
         [0047]     The load-control device  300  can be built into the relatively high-load device. The load-control device  300  can be added to a relatively high-load device as a retrofit. In one embodiment, the load-control device  300  is built into a circuit breaker, such as, for example, the double-pole circuit breakers  112 - 115  that provide power to a relatively high-load device.  
         [0048]      FIG. 4  shows a load-control and power monitoring device  400  that controls power to a relatively high-load device and that monitors power to the device. The system  400  is similar to the system  300 , and includes the electrical power inputs  320 ,  321 , the modem  301 , the power supply  302 , the power relay  309 , the processing system  304  and the memory  305 , the optional programming interface  306 , and the optional RF transceiver  307 . In the system  400 , a voltage sensor  401  measures the voltage provided to the terminals  330 ,  331  and a current sensor  402  measures the current provided to the terminal  330 . The voltage and current measurements from the sensors  401 ,  402  are provided to the processing system  304 .  
         [0049]     The load-control and power monitoring device  400  measures voltage and current at the output terminals  330 ,  331 . Thus, the device  400  can monitor and track the amount of power delivered to the load. In one embodiment, the device  400  keeps a log of power provided to the load in the log file stored in the memory  305 .  
         [0050]     The sensors  401 ,  402  are configured to measure electric power. In one embodiment, the sensor  401  measures voltage provided to a load and power is computed by using a specified impedance for the load. In one embodiment, the sensor  402  measures current provided to the load and power is computed by using a specified impedance or supply voltage for the load. In one embodiment, the sensor  401  measures voltage and the sensor  402  measures current provided to the load and power is computed by using a specified power factor for the load. In one embodiment, the sensor  401  measures voltage and the sensor  402  measures current, and power provided to the load is computed using the voltage, current, and the phase relationship between the voltage and the current.  
         [0051]     Voltage should not occur at the output terminals  330 ,  331  when the relay  309  is open. Thus, in one embodiment, the device  400  detects tampering or bypassing by detecting voltage at the output terminals  330 ,  331  when the relay  309  is open. In one embodiment, the modem  301  provides two-way communication and the processing system  304  sends a message to the power authority when tampering or bypassing is detected.  
         [0052]     Similarly, the current sensor  402  should detect current from time to time when the relay  309  is closed (assuming the electrical equipment provided to the output terminals  330 ,  331  is operational). Thus, in one embodiment, the device  400  detects the possibility of tampering or bypassing by sensing that current has been delivered to the attached equipment on a schedule consistent with the type of attached equipment.  
         [0053]      FIG. 5  shows a load-control and power monitoring device for controlling a relatively high-load device using relatively low power control, such as, for example, thermostat control lines. The system  500  is similar to the system  300  and includes the electrical power inputs  320 ,  321 , the modem  301 , the power supply  302 , the processing system  304  and the memory  305 , the optional programming interface  306 , and the optional RF transceiver  307 . In the system  500 , the power relay  309  is replaced by a relatively low-voltage relay  509 . Relay outputs  530 ,  531  can be used in connection with low-voltage control wiring (e.g., thermostat wiring, power relay control inputs, etc.) to control operation of a relatively high-load device.  
         [0054]     In one embodiment, the load-control device  500  (or the load-control devices  300 ,  400 ) allow the power authority to switch an electrical equipment device such as an air-conditioner into a low-power mode. For example, many higher-quality building air-conditioner systems have one or more low-power modes where the compressor is run at a lower speed. Thus, in one embodiment, the power authority can use the load-control device  500  to place the controlled electrical equipment in a low-power mode or into a shutdown mode. In one embodiment, a plurality of relays  509  is provided to allow greater control over the controlled device. Thus, for example, in one embodiment a first relay  509  is provided to signal the controlled device to operate in a low-power mode, and a second relay  509  is provided to signal the controlled device to shut down. Alternatively, two or more load-control devices  500  can be used for a single piece of electrical equipment. In one embodiment, a first load-control device having a first identification code is provided to signal the electrical equipment to operate in a low-power mode, and a second load-control device having a second identification code is provided to signal the electrical equipment to shut down.  
         [0055]      FIG. 7  shows a load-control and power-monitoring device  700  that controls power to a relatively high-load device and monitors current on multiple phases. The system  700  is similar to the system  400 , and includes the electrical power inputs  320 ,  321 , the modem  301 , the power supply  302 , the power relay  309 , the processing system  304  and the memory  305 , the optional programming interface  306 , the optional RF transceiver  307 , and the sensors  401 ,  402 . In the system  700 , a second current sensor  702  is provided to the processor  304 . The second current sensor  702  measures the current provided to the terminal  331 .  
         [0056]      FIG. 8  shows a load-control and power-monitoring device  800  that controls power to a relatively high-load device and that provides circuit breaker overload protection. The system  800  is similar to the system  700 , and includes the electrical power inputs  320 ,  321 , the modem  301 , the power supply  302 , the power relay  309 , the processing system  304  and the memory  305 , the optional programming interface  306 , the optional RF transceiver  307 , and the sensors  401 ,  402 ,  702 . In the system  800 , the input terminals  320  and  321  are provided to a double-pole circuit breaker  801 . Respective outputs of the double-pole circuit breaker  801  are provided to the modem  301 , the power supply  302 , and the relay  309 . When the circuit breaker  801  trips, the modem  301 , the power supply  302 , and the relay  309  are disconnected from the electric power inputs  320 ,  321 .  
         [0057]      FIG. 9  shows a load-control and power-monitoring device  900  that controls power to a relatively high-load device and that provides circuit breaker overload protection with electric trip. The system  900  is similar to the system  700 , and includes the electrical power inputs  320 ,  321 , the modem  301 , the power supply  302 , the power relay  309 , the processing system  304  and the memory  305 , the optional programming interface  306 , the optional RF transceiver  307 , and the sensors  401 ,  402 ,  702 . In the system  900 , the input terminals  320  and  321  are provided to a double-pole circuit breaker  801 . Respective outputs of the double-pole circuit breaker  901  are provided to the modem  301 , the power supply  302 , and the relay  309 . When the circuit breaker  901  trips, the modem  301 , the power supply  302 , and the relay  309  are disconnected from the electric power inputs  320 ,  321 . The circuit breaker  901  trips due to current overload in typical circuit-breaker fashion. In addition, an electric trip output from the processing system  304  is provided to an electric trip input of the circuit breaker  901  to allow the processing to tip the breaker  901 . In one embodiment, the processing system  304  trips the breaker  901  when an over-current condition is detected by one or more of the current sensors  402 ,  702 . In one embodiment, the processing system  304  trips the breaker  901  when a fault condition is detected. In one embodiment, the processing system  304  trips the breaker  901  when a ground-fault condition is detected. In one embodiment, the processing system  304  trips the breaker  901  when tampering is detected. In one embodiment, the processing system  304  trips the breaker  901  when an over-voltage condition is detected by the voltage sensor  401 . In one embodiment, the processing system  304  trips the breaker  901  when a trip command is received via the modem  301 . In one embodiment, the processing system  304  trips the breaker  901  when a trip command is received via the programming interface  306 . In one embodiment, the processing system  304  trips the breaker  901  when a trip command is received via the RF transceiver  307 . In one embodiment, the processing system  304  trips the breaker  901  when a fault is detected in the relay  309  (for example, the voltage sensor  401  can be used to detect when the relay  309  fails to open or close as instructed by the processing system  305 ).  
         [0058]      FIG. 10  shows a single-phase load-control and power-monitoring device  1000  that controls power to a relatively high-load device. The single-phase device  1000  is similar to the device  900  except that the relay  309  is replaced by a single-phase relay  1009 , the double-phase breaker  901  is replaced by a single-phase breaker  1001 . The input  320  is provided to the single-phase breaker  1001 . A neutral line input  1021  and the single-phase output from the breaker  1001  are provided to the modem  301  and the power supply  302 . The single-phase output from the breaker  1001  is provided to the single-phase relay  1009 .  
         [0059]     In one embodiment, the processing system  304  is provided with an identification code. In one embodiment, the identification code identifies the controlled electrical equipment provide to the terminals  330 ,  331  (or  530 , 531 ) and thus allows the load-control devices  250  to be addressed so that multiple pieces of electrical equipment can be controlled by providing one or more load-control devices to control each piece of electrical equipment. In one embodiment, the identification code is fixed. In one embodiment, the identification code is programmable according to commands received through the modem  301 . In one embodiment, the identification code is programmable according to commands received through the programming interface  306 . In one embodiment, the identification code is programmable according to commands received through the RF transceiver  307 .  
         [0060]     In one embodiment, the identification code used by the processing system  304  includes a device-type that identifies the type of equipment provided to the output terminals  330 ,  331  (or  530 ,  531 ). Thus, for example, in one embodiment the device-type specifies a type of device, such as, for example, a pool filter pump, an electric oven, an electric range, an electric water heater, a refrigerator, a freezer, a window air-conditioner, a building air-conditioner, etc. Relatively low-priority devices such as pool filter pumps can be shut down by the power authority for relatively long periods of time without harmful impact. Power overloads usually occur during the afternoon when temperatures are highest. Pool filter pumps can be run at night when temperatures are cooler and there is less stress on the power system. Thus, in one embodiment, the power authority can instruct the load-control devices having a device-type corresponding to a pool filter pump to shut down for relatively many hours, especially during the daytime.  
         [0061]     In one embodiment, the identification code includes a region code that identifies a geographical region. In one embodiment, the identification code includes an area code that identifies a geographical area. In one embodiment, the identification code includes one or more substation codes that identify the substations that serve power to the processing system  304 . In one embodiment, the identification code includes one or more transformer codes that identify the transformers that serve power to the processing system  304 .  
         [0062]     Other relatively high-load devices such as, for example, electric ovens, electric ranges, and/or electric water heaters, are perhaps more important than pool filter pumps, but relatively less important than air conditioners during the hottest part of the day (when power loads tend to be highest). Thus, if shutting down pool filter pumps, does not sufficiently reduce power usage, the power authority can then instruct the load-control devices having a device-type corresponding to such devices to shut down for extended periods of time, especially during the hottest part of the day, in order to reduce power usage. Such equipment can be shut down on a rolling basis over relatively limited areas or over a wide area. The shutdown of such equipment is perhaps more inconvenient than shutting down a pool filter pump, but less inconvenient that shutting down air-conditioners or refrigerators.  
         [0063]     If, after shutting down less important equipment, the power system is still overloaded, the power authority can proceed to shut down relatively more important equipment, such as building air-conditioners, window air-conditioners, etc. Such relatively important equipment can be shut down for limited periods of time on a rolling basis in order to limit the impact.  
         [0064]     In one embodiment, the system sensors  402 ,  702  and/or the voltage sensor  401  to measure and track the power provided to the attached device. The processing system  304  uses the sensor data to calculate system efficiency, identify potential performance problems, calculate energy usage, etc. In one embodiment, the processing system  304  calculates energy usage and energy costs due to inefficient operation. In one embodiment, the processing system  304  provides plots or charts of energy usage and costs. In one embodiment, the processing system  304  provides plots or charts of the additional energy costs due to inefficient operation of the attached electrical device.  
         [0065]     In one embodiment, the processing system  304  monitors the amount of time that the controlled electrical equipment has been running (e.g., the amount of runtime during the last day, week, etc.), and/or the amount of electrical power used by the controlled electrical equipment. In one embodiment, the power authority can query the processing system  304  to obtain data regarding the operation of the controlled equipment. The power authority can use the query data to make load balancing decisions. Thus, for example the decision regarding whether to instruct the controlled equipment to shut down or go into a low power mode can be based on the amount of time the system has been running, the home or building owner&#39;s willingness to pay premium rates during load shedding periods, the amount of power consumed, etc. Thus, for example a homeowner who has a low-efficiency system that is heavily used or who has indicated an unwillingness to pay premium rates, would have his/her equipment shut off before that of a homeowner who has installed a high-efficiency system that is used relatively little, and who had indicated a willingness to pay premium rates. In one embodiment, in making the decision to shut off the controlled equipment, the power authority would take into consideration the relative importance of the controlled equipment, amount of time the controlled equipment has been used, the amount of power consumed by the controlled equipment, etc. In one embodiment, higher-efficiency systems are preferred over lower-efficiency systems (that is, higher-efficiency systems are less likely to be shut off during a power emergency), and lightly-used systems are preferred over heavily-used systems (that is, lightly-used systems are less likely to be shut off during a power emergency).  
         [0066]     In one embodiment, the power authority knows the identification codes or addresses of the load-control devices and correlates the identification codes with a database to determine whether the load-control device is serving a relatively high priority client such as, for example, a hospital, the home of an elderly or invalid person, etc. In such circumstances, the power authority can provide relatively less cutback in power provided.  
         [0067]     In one embodiment, the power authority can communicate with the load-control devices to turn off the controlled equipment. The power authority can thus rotate the on and off times of electrical equipment across a region to reduce the power load without implementing rolling blackouts. In one embodiment, the load-control device is configured as a retrofit device that can be installed in a condenser unit to provide remote shutdown. In one embodiment, the load-control device is configured as a retrofit device that can be installed in a condenser unit to remotely switch the condenser-unit to a low power (e.g., energy conservation) mode. In one embodiment, the load-control device is configured as a retrofit device that can be installed in an evaporator unit to provide remote shutdown or to remotely switch the system to a lower power mode. In one embodiment, the power authority sends separate shutdown and restart commands to one or more load-control devices. In one embodiment, the power authority sends commands to the load-control devices to shutdown for a specified period of time (e.g., 10 min, 30 min, 1 hour, etc.) after which the system automatically restarts. In one embodiment, the specified period of time is randomized by the processor  304  to minimize power surges when equipment restarts. In one embodiment, the specified period of time is randomized according to a percentage (e.g., 5% randomization, 10% randomization, etc.)  
         [0068]      FIG. 6  shows a display system  600  for monitoring the load-control devices  300 ,  400 ,  500  in a home or building. In the device  600 , electrical power inputs  620 ,  621  are provided to an optional modem  601  and to a power supply  602 . Data from the modem  601  is provided to a processing system  604 . An optional programming interface  606  is provided to the processing system  604 . An optional Radio Frequency (RF) transceiver (having an antenna  608 ) is provided to the processing system  604 . A display  610  and a keypad  611  are provided to the processing system  604 .  
         [0069]     In one embodiment, the system  600  can be configured as a computer interface between the load-control devices and a computer, such as a personal computer, monitoring computer, PDS, etc. In one embodiment of the display system  600 , when used as an interface to a computer, the display  610  and keypad  611  can be omitted since the user can use the computer display and keyboard, mouse, etc.  
         [0070]     In one embodiment, the modem  601  facilitates one-way communication, to allow the processing system  604  to receive instructions and/or data from the injector  201 , from the load-control devices or from other power line communication devices. In one embodiment, the modem  601  facilitates two-way communication, to allow the processing system  604  to exchange instructions and/or data with the injector  201 , the load-control devices or other power line communication devices.  
         [0071]     The optional programming interface  606  can be configured as a computer port, such as, for example, a Universal Serial Bus (USB) port, a firewire port, an Ethernet port, a serial port, etc. In one embodiment, connection to the programming interface is  606  is provided by an external connector. In one embodiment, connection to the programming interface is provided by a magnetic coupling, a capacitive coupling, and/or an optical coupling (e.g., an InfraRed (IR) coupling, a visible light coupling, a fiber optic connector, a visible light coupling, etc.). The optional programming interface  606  can be configured to provide program code, identification codes, configuration codes, etc. to the programming system  604  and/or to read data (e.g., programming code, identification codes, configuration data, diagnostic data, etc.) from the programming system  604 .  
         [0072]     The optional RF transceiver  607  can be configured to provide communication with the processing system  604  through standard wireless computer networking systems, such as, for example, IEEE 802.11, bluetooth, etc. The optional RF transceiver  607  can be configured to provide communication with the processing system  604  through proprietary wireless protocols using frequencies in the HF, UHF, VHF, and/or microwave bands. In one embodiment, the antenna  608  is electromagnetically coupled to one or more electric circuits wires (such as, for example, the power input lines  620  or  621 , or other nearby electrical power circuits) so that the power circuits can operate as an antenna.  
         [0073]     The modem  601  receives modulated power line data signals from the power inputs  620 ,  621 , demodulates the signals, and provides the data to the processing system  604 . The processing system displays messages on the display  610  and receives user inputs from the keypad  611 . Thus, for example, the system  600  can use the display  610  to display messages from the power authority and/or messages from the load-control devices. The messages proved on the display  610  can relate to the power status of the various equipment controlled by load-control devices, such as, for example, power line load conditions, which equipment is about to be shut down, which equipment is shut down, how long equipment will be shut down, total power usage, power used by each piece of equipment, etc.  
         [0074]     In one embodiment, the programming system  604  obtains data from the log files stored in one or more of the load-control devices. In one embodiment, the display device  600  displays log file data, summaries of log file data, and/or plots of log file data from one or more of the load-control devices.  
         [0075]      FIG. 11  shows a conventional power meter assembly  1102  that plugs into a power meter box  1101  to provide electric service to a home or building. Electric power from the power local power company is provided on an input line  1108  to the meter box  1101 . An output line  1109  provides power from the power meter to the distribution box  103 . The power meter  1102  includes a conventional electric power meter  1103  used by the local power company to measure power provided to the home or building for billing purposes. When the power meter assembly  1102  is plugged into the meter box  1101 , the input  1108  is provided to the power meter  1103 , and an output of the power meter  1103  is provided to the output  1109 . The power meter  1103  typically includes a series of dials that display the amount of electric power delivered through the meter  1103 . In some localities, the power meter  1103  must be read manually. In some localities, the power meter  1103  is configured to be read remotely using an Automatic Meter Reading (AMR) system.  
         [0076]      FIG. 12  shows a power meter assembly  1200  with load control capability. The power meter  1200  is configured to plug into the conventional meter box  1101 . In the power meter  1200 , the input  1108  is provided to a load monitor  1201 . An output from the load monitor  1201  is provided to the power meter  1103 . The output of the power meter  1103  is provided to the output  1109 . One of ordinary skill in the art will recognize that the load monitor  1201  and the meter  1103  can be reversed such that the input  1108  is provided to the power meter  1103 , the output from the power meter  1103  is provided to the load monitor  1201 , and the output from the load monitor  1201  is provided  1201  is provided to the output  1109 . The load monitor  1201  can also be provided inside the meter box  1201  or the box housing the distribution panel  103 .  
         [0077]      FIG. 13  shows a load control assembly  1300  for use in connection with a standard power meter assembly  1102 . The load control assembly  1300  is configured to plug into the conventional power meter box  1101 . The load control assembly  1300  provides a conventional receptacle such that the standard power meter assembly  1102  can then be plugged into the load control assembly  1300 . In the load control assembly, the input  1108  is provided to the load monitor  1201 . An output from the load monitor  1201  is provided to the power meter assembly  1102 . The output of the power meter assembly  1102  is provide, via the assembly  1300 , to the output  1109 . One or ordinary skill in the art will recognize that the load monitor  1201  and the meter  1103  can be reversed such that the input  1108  is provided, via the assembly  1300 , to the power meter  1103 , the output from the power meter  1103  is provided to the load monitor  1201 , and the output from the load monitor  1201  is provided  1201  is provided to the output  1109 .  
         [0078]     The load monitor  1201  provides load control and monitoring as described in connection with  FIGS. 3-5  and/or  7 - 10 . In one embodiment, the power authority sends instructions to the load monitor  1201  using power line networking via the modem  301 . In one embodiment, the power authority sends instructions to the load monitor  1201  using power line networking via programming interface  306  (e.g., through a wired network connection, telephone connection, cable connection, fiber-optic connection, etc.). In one embodiment, the power authority sends instructions to the load monitor  1201  using wireless transmission via the transceiver  307 .  
         [0079]     In one embodiment, the load monitor  1201  is provided in the distribution box  103  in series with the master breaker  104 . In one embodiment, the load monitor  1201  is provided to the master breaker  104 . In one embodiment, the load monitor  1201  is built into the master breaker  104 .  
         [0080]     In one embodiment, the load monitor  1201  is configured as shown in FIGS.  4  and/or  7 - 10  and programmed to operate such that the power authority can command the processor  304  to allow no more than a specified maximum amount of power (or current) is delivered through the load monitor  1201 . Thus, for example, even if the power meter  102  and master breaker  104  are configured for  200  amp service (as is typical of many residential installations), then during a power shortage, the power authority can instruct the load monitor to open the relay  309  (and thus blackout the home or building served by the load monitor  1201 ) if the current exceeds a specified maximum (e.g.,  20  amps,  30  amps,  50  amps,  100  amps, etc.), during some period of time. In one embodiment, the load monitor  1201  restores power service after a specified period of time. In one embodiment, the load monitor  1201  restores power service after the power authority sends instructions or commands to the load monitor  1201  informing the load monitor  1201  that more power is available. In one embodiment, after receiving commands to reduce power, the load monitor  1201  delays transitioning to low-power mode for a period of time in order to give downstream load control devices, such as the load-control devices  250 , time to reduce the power load. In one embodiment, after receiving commands to reduce power, the load monitor  1201  delays transitioning to low-power mode for a period of time in order to give the home or building owner time to reduce the power load.  
         [0081]     Thus, the load monitor  1201  provided in the service line can be used with or without the load control devices  250  provided with specified circuits (or loads) in the home or building to provide load control. The load monitor  1201  and/or load control devices  205  can be used on a voluntary basis, in connection with a regulatory scheme, or some combination thereof. For example, a regulatory scheme can be adopted that requires load control devices  250  in certain relatively high-load circuits (e.g., pool filter pumps, electric water heaters, electric ovens, air-conditioners, etc.).  
         [0082]     Alternatively, a regulatory scheme can be adopted that requires the load control device  1201  be installed at the service entrance while leaving it up to the homeowner or building owner to voluntarily install the load control devices  250  in various circuits. Under such a regulatory scheme, a home owner that does not install load control devices  250  in the relatively high-load circuits of the home or building runs the risk of losing service during a power shortage because the load control device  1201  will act like a circuit breaker and “trip” if the owner tries to draw more power than the power authority has authorized during the power shortage. Unlike a regular circuit breaker, in such a regulatory scheme, the load control monitor  1201  can be configured so that it cannot be immediately reset and thus the owner will have to endure a blackout period. Thus, under such a regulatory scheme, it is in the owner&#39;s best interests to voluntarily install the load control devices  250  so that the total load through the load monitor device  1201  is less than the allowed load during the power shortage.  
         [0083]     In one embodiment, the load monitor device  1201  uses the modem  301 , the programming interface  306  and/or the RF transceiver  307  to send status and/or shutdown messages to the load control devices  250  and/or the display device  600 . A load control system based on the load monitor device  1201 , the load control devices  205 , and the display device  600  (or computer) is flexible and can be configured to operate in different ways.  
         [0084]     In one embodiment, the load monitor device  1201  receives a load-limit message from the power authority instructing the load monitor device  1201  to limit power or current drawn through the building&#39;s electrical service. The load monitor device  1201  then selects the circuits to shut down (based on the allowed current) and sends shutdown commands to the various load control devices  250 . In one embodiment, the display system  600  (or computer) also receives the shutdown commands and can format a display showing which devices have been shut down. In one embodiment, the load monitor device  1201  sends one or more status messages to the display system  600  (or computer) to allow the display system  600  inform the owner of the power status (e.g., which devices have been shut down, how long the shutdowns will last, how much power is allowed, etc.)  
         [0085]     In one embodiment, the load monitor device  1201  receives a load-limit message from the power authority instructing the load monitor device  1201  to limit power or current drawn through the building&#39;s electrical service. The load monitor device  1201  then sends a message to the display system  600  (or computer) informing the display system of the power restriction. The display system  600  (or computer) selects the circuits to shut down (based on the allowed current) and sends shutdown commands to the various load control devices  250 . The display system  600  (or computer) formats a display to inform the owner of the power status (e.g., which devices have been shut down, how long the shutdowns will last, how much power is allowed, etc.). In one embodiment, the owner can use the display system  600  (or computer) to select which devices will be shut down and which devices will remain operational. Thus, for example, during an extended power outage, the owner can rotate through the relatively high-load devices first using the air-conditioner (with the hot-water heater shut down) and then using the hot-water heater (with the air-conditioner shut down). The owner can also use the display system  600  (or computer) to establish power priorities and determine the order in which circuits are shut down based on the available power. Thus, for example, in winter, the homeowner can choose to shut down all circuits except the electric heater (or heat pump), while in summer the same homeowner might decide to shut down the air-conditioner before shutting down the electric water heater. Thus, in one embodiment, when the total power is limited by the load monitor device  1201 , the homeowner (or building owner) can use the display system  600  (or computer) to make decisions regarding which devices are shut down and in what order. In one embodiment, the display system  600  (or computer) knows the power (or current) drawn by each piece of electrical equipment serviced by a load-control device  250  and thus the display system  600  (or computer) can shut down the required number of devices based on the priorities established by the user (or based on default priorities).  
         [0086]     In one embodiment, a regulatory scheme requires load-control devices  250  for all relatively high-load devices in a home or building. In one embodiment, the power authority shuts down the relatively high-load equipment based one a priority schedule (e.g., pool filter pumps first, then ovens and stoves, then electric water heaters, then air-conditioners, then heaters, etc.) until the system load has been sufficiently reduced. In one embodiment, the power authority shuts down the relatively high-load equipment based on location (e.g., first one neighborhood, then another neighborhood) in a rolling fashion until the system load has been sufficiently reduced. In one embodiment, the priority schedule is established by the power authority. In one embodiment, the priority schedule is established by the home or building owner.  
         [0087]     In one embodiment, the priority schedule is adaptive such that a group of load control devices  205  negotiate to determine the priority. In one embodiment, heating devices have a relatively higher priority in winter (e.g., less likely to be turned off) and a relatively lower priority in summer.  
         [0088]     In one embodiment, a regulatory scheme requires both load monitoring devices  1201  and load-control devices  250 .  
         [0089]     In one embodiment, the processing system is configured to support encrypted communication through the modem  301 , the programming interface  306 , and/or the RF transceiver  307  to prevent unauthorized access. In one embodiment, a first encryption is used for communication with the processing system  304  related to load reduction commands such that only the power authority has the ability to send load reduction commands to the processing system  304 . In one embodiment, a second encryption is used for communication with the processing system  304  related to status and power usage information so that the home or building owner can use the display system  600  and/or a computer to make inquires to the processing system  304  regarding power usage, power status, etc. Using two different encryptions, allows the power authority to control the processing system  304  to reduce loads on the power system, while still allowing the home or building owner to make inquiries to the processing system  304  (while preventing neighbors and other unauthorized persons to access the system  304 ).  
         [0090]     In one embodiment, the first and second encryptions are provided by using first and second passwords. In one embodiment, the first and second encryptions are provided by using first and second encryption methods.  
         [0091]     In one embodiment, encrypted access is provided via one communication method (e.g., through a selected frequency band or bands via modem  301 , through one or more access methods provided by the programming interface  306 , and/or though a selected frequency band or bands via the transceiver  307 . Thus, by way of example, and not by way of limitation, in one embodiment, the processor  304  can be configured such that commands from the power authority are received via the RF transceiver  307 , communication with the display system  600  or computer are provided by the modem  301 , and configuration of the processing system  304  (e,g., entry of passwords) is provided by communication using the programming interface  306 .  
         [0092]     In one embodiment, the relay  309  is configured such that when the relay  309  is open, power line networking signals from the modem  301  are still provided to the output terminals  330 ,  331 . In one embodiment, the relay  309  includes a high-pass filter to allow powerline-networking signals from the modem  301  to flow though the relay when the relay is open. In one embodiment, the relay  309  includes a band-pass filter to allow powerline-networking signals from the modem  301  to flow though the relay when the relay is open.  
         [0093]     In one embodiment, the circuit breakers  801 ,  901  are configured such that when the breaker  801 ,  901  is tripped (open), power line networking signals from the modem  301  are still provided to the input terminals  320 ,  321 . In one embodiment, circuit breakers  801 ,  901  are bypassed by a high-pass filter to allow powerline-networking to flow through the breaker when the breaker is open. In one embodiment, the circuit breakers  801 ,  901  include a band-pass filter to allow powerline-networking to flow though the breaker when the breaker is open.  
         [0094]     In addition to providing load control for the power authority, the systems described herein can be used for load control by the home or building owner to track power usage and reduce power costs. Thus, for example, when the load monitor device  1201  is configured using embodiments that include the current sensors  402 ,  702 , the load monitor device  1201  can provide current usage (and thus power usage) data to the display system  600  (or computer). When the load-control devices  250  are configured using embodiments that include the current sensors  402  and/or  702 , the load-control devices  250  can provide current usage (and thus power usage) data to the display system  600  (or computer) for the electrical equipment serviced by the load-control device.  250 .  
         [0095]     In one embodiment, the modem  301  is configured to operate in a plurality of powerline networking modes such as, for example, BPL, X10, LonWorks, current carrier, etc. In one embodiment, the modem  301  communicates with the power authority using a first power line networking protocol, and the modem  301  communicates with the display  600  or computer using a second power line networking protocol.  
         [0096]     In one embodiment, the modem  301  is omitted. In one embodiment, the transceiver  307  is omitted. In one embodiment, the programming interface  306  is omitted.  
         [0097]     In one embodiment, the relay  309  is configured to close in a manner that provides a “soft” restart of the electrical equipment in order to reduce surges on the power line. In one embodiment, the relay  309  is configured as a solid state relay and the processing system  304  controls the solid state relay in a manner that provides a soft restart. In one embodiment, the relay  309  is configured as a solid state relay and the processing system  304  controls the solid state relay in a manner that provides a soft restart by progressively switching cycles of the AC power on the power line.  
         [0098]     In one embodiment, the relay  309  is configured to close in a manner that provides a dimmer-like function such that resistive electrical equipment such as for example, electric water heaters, electric ovens and ranges, resistive electric heaters, and the like can be controlled at reduced power levels without be shut completely off. In one embodiment, the relay  309  is configured as a solid state relay and the processing system  304  controls the solid state relay in a manner that provides a dimmer-like function. In one embodiment, the relay  309  is configured as a solid state relay and the processing system  304  controls the solid state relay in a manner that provides a dimmer-like function by progressively switching selected cycles, or portions of cycles, of the AC power on the power line.  
         [0099]      FIG. 14  shows an electric distribution system  1400  with automatic downstream load control. In the system  1400 , power is provided to a substation  1401 . The substation  1401  provides power to a plurality of substations  1411 - 1414 . Each of the substations  1411 - 1414  provides power to a plurality of transformers that service homes, neighborhoods, or buildings. In  FIG. 14 , the substation  1413  provides power to a plurality of transformers  1421 - 1424 . The Transformer  1421  provides power to a plurality of homes  1431 - 1435 . A load sensor  1450  is provided to the substation  1413 . A load sensor  1451  is provided to the transformer  1451 .  
         [0100]     When the substation  1413  becomes overloaded (or nears overload), the load sensor  1450  sends load reduction signals to the homes and buildings serviced by the substation  1413 . Thus, in  FIG. 14 , when the load sensor  1450  detects that the substation  1413  is overloaded, the sensor  1450  sends load reduction commands to the homes/buildings serviced by the transformers  1421 - 1424 . In one embodiment, the load sensor  1450  uses powerline networking to send load reduction commands to the homes/buildings serviced by the transformers  1421 - 1424 . In one embodiment, the load sensor  1450  uses wireless transmission to send load reduction commands to the homes/buildings serviced by the transformers  1421 - 1424 . In one embodiment, the load sensor  1450  also informs the power authority that the substation  1413  is overloaded.  
         [0101]     When the transformer  1421  becomes overloaded (or nears overload), the load sensor  1451  sends load reduction signals to the homes and buildings serviced by the transformer  1421 . Thus, in  FIG. 14 , when the load sensor  1451  detects that the transformer  1421  is overloaded, the sensor  1451  sends load reduction commands to the homes  1431 - 1435 . In one embodiment, the load sensor  1451  uses powerline networking to send load reduction commands to the homes  1431 - 1435 . In one embodiment, the load sensor  1451  uses wireless transmission to send load reduction commands to the homes  1431 - 1435 .  
         [0102]     Although various embodiments have been described above, other embodiments will be within the skill of one of ordinary skill in the art. Thus, the invention is limited only by the claims.