Abstract:
An intelligent demand controller protects the local customer premises supply transformer from overload and senses conditions on the transformer. The intelligent demand control system utilizes a communications network with a plurality of load control units having a unique address and residing at a plurality of customer premises. A demand controller monitors the voltages and frequency of electricity provided to the customer premises as well as the instantaneous current required by the operating loads of the customer premises. Each of the plurality of demand controllers may be associated with one or more of a plurality of load control units and configured to receive data related to the state of the power supplied to the plurality of controlled loads and generate a transmit message using a predefined communication protocol. When certain programmable conditions are met, a load control unit is signaled to remove power from one or more of its monitored loads.

Description:
TECHNICAL FIELD OF THE INVENTION 
   The present invention generally relates to controlling power demand in an electric power distribution system and, in particular, to a system and method for intelligently limiting power demand at customer premises through cycle-by-cycle monitoring of electricity provided to the customer premises, as well as monitoring of load operation by a load control unit. 
   BACKGROUND OF THE INVENTION 
   Electric utilities or distribution organizations, hereafter referred to as electricity suppliers, are responsible for supplying an economic, reliable and safe source of electricity to customers. The electricity supplier, through its&#39; energy delivery system, provides electricity to its customers at a suitable voltage and frequency. This electricity is provided on an instantaneous basis. That is, when the customer turns on an appliance, the electricity supplier provides the electricity to the customer&#39;s appliance the instant that the customer flips the switch on. 
   One well-known difficulty in providing electricity to customers is precisely matching the total amount of electricity consumed by all of the customers on an instantaneous basis with the amount of electricity generated and/or purchased by the electricity supplier. The total amount of electricity used at any given instant in time is commonly referred to as demand. Demand typically is measured in units of watts, kilo-watts (KW), or mega-watts (MW). For example, a conventional light bulb may have a demand of 100 watts. Ten (10) of these light bulbs has a demand of 1 KW. If one thousand of these light bulbs are all turned on at the same instant in time, the electricity supplier must instantly provide an additional 100 KW of electricity by increasing generation and/or purchases. 
   Most changes in demand, either up or down, are a small percentage of the overall delivery system load and result in little, if any, mismatch between supply and demand. This minor mismatch rarely causes a measurable change in system voltage or frequency. Significant mismatches between demand and supply occur when either the delivery system or supply (generation and/or purchases) cannot meet demand. As this mismatch increases, a voltage drop starts to occur. When significant mismatches between demand and supply occur, distortion in the electric system frequency occurs. 
   Currently there are devices designed to automatically remove loads when either voltage or frequency are out of tolerance, both at the appliance and system level. 
   U.S. Pat. No. 6,541,740 entitled “Heater/Blower Unit With Load Control” which issued on Apr. 1, 2003 to Ziaimehr et al. uses a two-heater system with a method of minimizing fluctuations in the load on a high wattage electrical device. 
   U.S. Pat. No. 6,671,586 entitled “System and Method for Controlling Power Demand over an Integrated Wireless Network” which issued on Dec. 30, 2003 to Davis et al. discloses an intelligent network demand control system which employs a transceiver network coupled to meters and appliances. 
   U.S. Pat. No. 6,836,737 entitled “Systems and Methods for Providing Remote Monitoring of Consumption for a Utility Meter” which issued on Dec. 28, 2004 to Petite et al. discloses a plurality of electric meters and communications devices which define a wireless communications network for controlling the consumption of electric power. 
   U.S. Pat. No. 6,862,498 entitled “System and Method for Controlling Power Demand over an Integrated Wireless Network” which issued on Mar. 1, 2005 to Davis et al. provides an intelligent demand control system for an energy delivery system using a wireless transceiver network for reducing energy demand as needed. 
   As another example, if the electricity supplier loses a generator in an unplanned manner, the electric system demand will exceed supply. If the mismatch is sufficiently large, the electric frequency will drop from its nominal value of 60 hertz (Hz), in the United States. If the frequency drops to below 59.8 Hz, relays sense the frequency decay and operate to selectively disconnect predefined groups of customers from the energy delivery system. Demand is reduced, hopefully to the point where demand again approximately equals supply such that the frequency recovers back to its nominal 60 Hz value. Disconnecting customer loads to arrest frequency decay is known as load shedding. 
   Although the action of the frequency sensitive relays effectively arrests the undesirable frequency decay, thereby saving the energy delivery system from a more severe decay in frequency and other undesirable associated problems, those customers that were disconnected did not volunteer to be selected as participants in the load-shedding scheme. Furthermore, the electricity supplier loses the associated sales to the affected customers, thereby negatively impacting the electricity supplier&#39;s revenue stream. 
   One well-known technique to decrease the frequency of occurrence of these undesirable mismatches between energy demand and supply is to couple selected energy consuming loads to radio frequency (RF) controlled receivers. Then, when a mismatch in demand and supply occurs, or when the electricity supplier anticipates that a mismatch occurrence is eminent, the electricity supplier orders the shut off of the selected energy consuming loads by transmitting a shut-off signal to the RF receivers. Such a group of aggregated loads is commonly referred to as a load block. Participation in such a load block is typically voluntary. Often, customers are offered incentives to participate. For example, a customer can be given a decrease in rate and/or a rebate to voluntarily allow the electricity supplier to couple an RF receiver to their load. 
   The previous example is based upon mismatches when supply (generation and/or purchases) does not match demand. Mismatches occurring due to the delivery system inadequacies are something that the electricity supplier cannot easily monitor or correct. A local customer premises transformer can be overloaded due to concurrent demands from each of the residences. Also a transformer that is feeding a plurality of customer premises transformers can become overloaded without affecting the majority of the delivery system. These types of problems are very expensive for an electricity supplier to remedy, as it involves major changes to the delivery system. 
   With all of these methodologies, the electricity supplier is still faced with the peak demands that are placed on the energy delivery system everyday. Many electricity suppliers offer rate structures that provide an incentive to utilize power during typical ‘off-peak’ times. This approach may limit demand peaks during one time frame, however it most often causes another. Electricity suppliers can increase generating capacity and/or purchase additional power to support these peak demands. Either approach means that the cost of the electricity is more than during normal operation, thereby negatively impacting the electricity supplier&#39;s revenue stream. 
   Yet another problem that the electricity supplier faces is the power factor issue that occurs due to HVAC units (or any significant motor load). Some electricity suppliers utilize constant voltage transformers (CVT) to help offset power factor influences. Another philosophy is to switch large banks of capacitors in or out of a circuit as necessary. This is not typically an approach that can be used to correct a power factor issue quickly, as personnel must be sent out to switch these banks. Most implementations of capacitor bank switching is done on a seasonal basis, due to anticipated motor loads. Some electricity suppliers have implemented capacitor bank switching at the substation level and do so without requiring personnel to be sent out. This still does little to affect the more local overloading that occurs due to power factor influences. 
   Thus, a need exists in the industry for providing a demand limiting and control system that accurately monitors the supplied electricity and intelligently determines the need for load shedding, in real time. Also, there is a need in the industry to provide a system that allows for selective determination of the best combination of loads to meet the desired reduction. There is also a need to allow the customer to determine what load(s) is available for shut-off. And finally a need in the industry is to control power factor throughout the energy delivery system such that energy losses due to overheating of components is reduced to a minimum. 
   The present invention meets these needs. 
   SUMMARY OF THE INVENTION 
   The present invention overcomes the inadequacies and deficiencies of the prior art as discussed herein above. One embodiment of the present invention, an intelligent demand limiting system, provides a system and method for monitoring an electricity source and determining the conditions under which the local supply transformer is operating. The intelligent demand limiting system employs a communication network with a plurality of demand controllers residing at a plurality of customer premises. Each demand controller is in direct communications with a plurality of load control units. Customer premises load control units are coupled to loads located in the plurality of customer premises. The demand controllers and load control units each have unique identification codes. In one embodiment, the demand controller analyzes the customer premises electricity supply and determines the state of the local supply transformer. 
   This state may be a local overload condition, or a more serious system wide problem. In either case, operating conditions that are outside of the expected norm are compensated for by limiting the demand placed on the local supply transformer. When a plurality of demand controllers, at a plurality of customer premises, are monitoring electricity from a common transformer, these intelligent controllers will negotiate the appropriate action. The processing of the information relative to the state of the local supply transformer allows any or all loads to be shut-off within one cycle (16.6 milliseconds) of an out-of-norm condition. The monitoring capabilities of the load control unit(s) provide real time information relative to the operating state of all attached loads. 
   In one embodiment, the electricity supplier may communicate with the demand controller for purposes of adjusting the trigger points utilized to define out-of-norm conditions. This communication method uses standardized digital communication formats such that the information is communicated as packetized units of digital data. Other embodiments employ other suitable communication formats. The communications format and method are outside the scope of this disclosure. 
   In another embodiment, the electricity supplier may retrieve information stored by the demand controller for purposes of evaluating transformer sizing and/or patterns of out-of-norm conditions. 
   Other features and advantages of the present invention will become apparent to one skilled in the art upon examination of the following detailed description, when read in conjunction with the accompanying drawings. It is intended that all such features and advantages be included herein within the scope of the present invention and protected by the claims. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The invention can be better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the invention. Furthermore, like reference numerals designate corresponding parts throughout the several views. 
       FIG. 1  is a block diagram illustrating a portion of a plurality of demand controllers residing at a plurality of customer premises, and fed by a common customer premise transformer. 
       FIG. 2  is a block diagram illustrating selected components residing at one of the exemplary customer premises of  FIG. 1 . 
       FIG. 3  is a block diagram illustrating an embodiment of a customer premises demand controller and communications system residing at the customer premises of  FIG. 2 . 
       FIG. 4  is a block diagram illustrating one embodiment of a customer premises load controller residing at the customer premises of  FIG. 2 . 
       FIG. 5  is a block diagram illustrating another embodiment of a customer premises load controller residing at the customer premises of  FIG. 2 . 
       FIG. 6  is a block diagram illustrating an embodiment of a customer premises capacitance controller residing at the customer premises of  FIG. 2 . 
       FIG. 7  is a flow chart illustrating a process for determining the state of the customer premises transformer, and thereby the state of its&#39; primary supply system. 
       FIG. 8  is a normalized real-world waveform shown in comparison to an ideal sinusoid. 
   

   DETAILED DESCRIPTION 
   In general, the present invention relates to a system and method for providing an electricity supplier indirect control over selected customer loads such that the controlled loads are selectively shut off during periods of time when the electricity source is operating outside of defined parameters. Local analysis of the energy delivery system provides for early warning and abatement based upon minor deviations in the electricity source. This early warning allows the energy delivery system to maintain an electricity source to all customers with a minimum of inconvenience, and thereby minimally impacting the electricity supplier&#39;s revenue steam. System demand is defined herein to be the instantaneous amount of electricity, including customer loads and electric system transmission losses, that the electricity supplier either generates or purchases to provide service to its customers. Customers are defined herein to include residential customers (individuals or families living in homes, apartments, condominiums or the like), retail customers (such as retail stores, shopping malls, small businesses or the like) and wholesale customers (such as manufacturers, producers or the like). Although the characteristics of residential customers, retail customers and wholesale customers are very different from each other, the intelligent demand control system is designed to apply equally well to any customer class. 
   It should be noted that all references to defined parameters within this specification are typically derived from logged data specific to a customer premises transformer. Initial values are used to approximate conditions at a customer premises transformer, however actual operational data is used to modify these values based upon real world conditions. Main feed length and size, from the customer premises to the customer premises transformer, is just one of the factors considered in modifying the defined parameters. 
     FIG. 1  is a block diagram illustrating a portion of a plurality of demand controllers  103  residing at a plurality of customer premises  104 , and fed by a common customer premises transformer  101 . As best seen in  FIG. 2 , each demand controller  103 , described in more detail below, is coupled to the main feed electrical lines  110  at the meter  102  of customer premises  104 . Upon detecting line conditions that are outside of defined parameters, demand controller  103  sends a command via a communications link  107  to one or more of a plurality of load controllers  105  to shut off one or more loads on the one or more load controllers  105 . In one embodiment, the plurality of demand controllers  103  residing at each of the plurality of customer premises  104  are being supplied by customer premises transformer  101  communicate with each other via communications link  107  to determine a response to the line condition parameters. The system and method for these communications may include, but is not limited to, a public switched telephone network  341 , a digital communications system  342 , or a utility communications system  343 , as referenced in  FIG. 3 . The representation of a water heater  109  and an HVAC unit  108  is for demonstration purposes only and may in fact be any load. 
   As best seen in  FIG. 2 , demand controller  103  monitors the main feed electrical lines of customer premises  104  with a plurality of current transformers  206  and voltage transformers  207  on a cycle-by-cycle basis. In one embodiment, an electricity supplier  201  can set the defined parameters that cause a controlled load to be shut off. Additional parameters could be set to determine the conditions under which the shed load(s) would be allowed to resume operation. A graphical display module  202  and/or a personal computer  203  are utilized to allow the customer to identify and prioritize which load(s) may be shut off when a line condition is outside of defined parameters. In one embodiment, an HVAC load controller  205  may be utilized to control the operation of an HVAC unit  108  by interrupting a control line  208  between a thermostat  204  and HVAC unit  108 . In this embodiment a multi-stage HVAC unit can be controlled to provide the necessary load reduction while causing a minimal inconvenience to the customer. 
     FIG. 3  is a block diagram illustrating an embodiment of customer premises demand controller  103  and communications system residing at customer premises  104  of  FIG. 2 . Demand controller  103  includes at least a micro-controller  301 , an interface  302 , a storage  310 , a memory  320 , and an analog front end processor  330 , such as the commercially available ADE7753 from Analog Devices or equivalent. Storage  310  includes at least a set of operational parameters  312  and a log  311 . Memory  320  includes at least a control logic  321  and a set of default parameters  322 . 
   When analog front end processor  330  senses a zero-cross condition, micro-controller  301  is signaled via connection  303 . The micro-controller  301  retrieves and executes the control logic  321  from memory  320 , via connection  304 , to retrieve the line condition information from analog front end processor  330 , via connection  303 , and executes the control logic  321  to compare these line conditions with the defined parameters. If one or more of these conditions are outside of the defined parameters, micro-controller  301  will read the operational parameters  312  from storage  310 , via connection  305 . From these operational parameters  312 , the micro-controller  301  will determine what operating load(s) can be shed in order to bring the line conditions back within defined parameters. The micro-controller  301  will, via connection  306  to interface  302 , transmit a command to one or more of load controllers  105  or HVAC load controllers  205 , each of which is designated by a unique address, to shut off a load(s), also designated by a unique address, via a connection  307 . 
   Irrespective of a line condition being outside of defined parameters, micro-controller  301  will retrieve and execute the controller logic  321  from memory  320 , via connection  304  to process and summarize the line condition information. Micro-controller  301  will store the line condition information in the logs  311  of storage  310 , via connection  305 . 
   A communications module  340  provides electrical, signal, and protocol conversion between the interface  302  and the outside world. These converted communication systems include, but are not limited to, public switched telephone network  341 , digital communications system  342 , or legacy communications system  343 , as referenced in  FIG. 3 . 
   In one embodiment, the components (not shown) residing in communications module  340  that are configured to transmit, receive and convert signals from the public switched telephone network  341  are well known in the art and, therefore, are not described in detail herein. One skilled in the art will realize that such well known components are too numerous to describe in detail herein, and that any configuration of such well known components having the above-described functionality may be implemented in communications module  340 . Any such implementation of components configured to receive and convert communication signals from public switched telephone network  341  are intended to be within the scope of this disclosure and to be protected by the accompanying claims. 
   Another embodiment of the communications module  340  is configured to transmit, receive and convert signals utilizing legacy communication system  343 . The components (not shown) residing in the communications module  340  that are configured to transmit, receive and convert signals from the legacy communication system  343  are well known in the art and, therefore, are not described in detail herein. One skilled in the art will realize that such well known components are too numerous to describe in detail herein, and that any configuration of such well known components having the above-described functionality may be implemented in the communications module  340 . Any such implementation of components configured to receive and convert communication signals from the legacy communication system  343  are intended to be within the scope of this disclosure and to be protected by the accompanying claims. The legacy communication system  343  is a conventional integrated network of communication technologies that may include conventional wire based communication systems, radio frequency communications, microwave communication systems, powerline communication systems or fiber optics networks. For example, communications module  340  may integrate an radio frequency transceiver to provide connectivity between demand controllers  103  at the plurality of customer premises  104 . 
   In yet another embodiment of the communications module  340 , it is configured to communicate via conventional digital communication system  342 . The components (not shown) residing in communications module  340  that are configured to transmit, receive and convert signals from digital communication system  342  are well known in the art and, therefore, are not described in detail herein. One skilled in the art will realize that such well known components are too numerous to describe in detail herein, and that any configuration of such well known components having the above-described functionality may be implemented in the communications module  340 . Any such implementation of components configured to receive and convert communication signals from the digital communication system  342  are intended to be within the scope of this disclosure and to be protected by the accompanying claims. The digital communication system  342  is a conventional based communication system configured to communicate information in a digital format and may include, but is not limited to, public switched telephone network, powerline, frame relay and/or cable network. Protocols used over these communication systems are well known in the industry and beyond the scope of this document. An example of this embodiment would be a communications module configured to communicate via TCP/IP over a powerline to provide connectivity between demand controller  103  and electricity supplier  201 . 
   The components (not shown) residing in demand controller  103  that are configured to convert and transmit power to the components thereof are well known in the art and, therefore, are not described in detail herein. One skilled in the art will realize that such well known components are too numerous to describe in detail herein, and that any configuration of such well known power supply components may be implemented in demand controller  103  without departing substantially from the operation and functionality of the demand controller  103  as described herein. Any such implementation of the components configured to provide power to the components of demand controller  103  are intended to be within the scope of this disclosure and to be protected by the accompanying claims. 
     FIG. 4  shows one embodiment of a load controller  105  residing at customer premises  104 . Load controller  105  includes at least a micro-controller  401 , an interface  402 , and a memory  410 . Memory  410  includes at least a control logic set  411  and a set of default parameters  412  including a unit address. Additionally, load controller  105  includes relays  403  and  404  connected to micro-controller  401 , via connections  407  and  408 , respectively. The load controlled by relay  403  is monitored by micro-controller  401  via connection  416  with current transformer  405 . The load controlled by relay  404  is monitored by micro-controller  401  via connection  417  with current transformer  406 . 
   When micro-controller  401  receives a shut off command through interface  402 , via connection  415 , micro-controller  401  retrieves the unit address stored in memory  410  at default parameters  412 . Micro-controller  401  retrieves the load controller control logic  411  from memory  410  and executes the control logic to compare the unit address stored in memory  410  at defaults  412  with the received unique address of the command. If the unit address matches the received command address, micro-controller  401  provides a shut off control signal to the specific relay(s)  403  and/or  404  designated in the received command. 
   When micro-controller  401  has set relay  403  or  404  to allow the attached load to operate, micro-controller  401  monitors current transformers  405  and  406 , via connections  416  and  417 , respectively. When the attached load is operating, micro-controller  401 , via connection  415  to interface  402 , notifies demand controller  103  of this condition during the next communication cycle. 
   In another embodiment of the HVAC load controller  205  shown in  FIG. 5 , HVAC load controller  205  includes at least a micro-controller  421 , an interface  422 , and a memory  440 . Memory  440  includes at least a control logic set  441  and a set of default parameters  442  including a unique unit address. Additionally, load controller  205  includes relays  423 ,  424 , and  425  connected to micro-controller  421 , via connections  429 ,  430 , and  431 , respectively. 
   When micro-controller  421  receives a shut off command through interface  422 , via connection  436 , micro-controller  421  retrieves the unit address stored in memory  440  at defaults  442 . Micro-controller  421  retrieves the load controller control logic  441  from memory  440  and executes the control logic to compare the unit address stored in memory  440  at defaults  442  with the received unique address of the command. If the unit address matches the received command address, micro-controller  421  provides a shut off control signal to the specific relay(s)  423 ,  424 , and/or  425  designated in the received command. 
   In addition, micro-controller  421  monitors opto-sensors  426 ,  427  and  428 , via connections  429 ,  430  and  431 , respectively. When thermostat  204 , calls for a load attached to relays  423 ,  424  or  425 , opto-sensors  426 ,  427  or  428  provide a signal to micro-controller  421 , via connections  429 ,  430  or  431 , respectively. The signal is received even when the respective relay is open. Micro-controller  421 , via connection  436  to interface  422 , will notify demand controller  103  of this condition during the next communication cycle. 
     FIG. 6  is a block diagram illustrating an embodiment of a customer premises capacitance controller residing at the customer premises of  FIG. 2 . This embodiment of demand controller  103  utilizes the power factor information for the customer premises to determine an amount of capacitance that is needed to achieve unity power factor. The capacitance controller  601  includes at least a micro-controller  621 , an interface  622 , and a memory  640 . Memory  640  includes at least the control logic  641  and default parameters  642 . Additionally, capacitance controller  601  includes relays  623 ,  624 ,  625 , and  626  connected to micro-controller  621 , via connections  631 ,  632 ,  633 , and  634 , respectively. These relays can be mechanical or solid state, as determined by best suitability for service. The relays  623 ,  624 ,  625 , and  626  control the connection of capacitors C 1 , C 2 , C 3 , and C 4 , respectively, to the electrical service. The sizing of C 1 , C 2 , C 3 , and C 4  is dependent upon the estimated total reactive load at the customer premises. 
   When micro-controller  621  receives a close command through interface  622 , via connection  636 , micro-controller  621  retrieves the unit address stored in memory  640  at defaults  642 . Micro-controller  621  retrieves the capacitance controller control logic  641  from memory  640  and executes the control logic to compare the unit address stored in memory  640  at defaults  642  with the received unique address of the command. If the unit address matches the received command address, the micro-controller  621  provides a close control signal to the specific relay(s)  623 ,  624 ,  625 , and/or  626  designated in the received command. 
     FIG. 7  shows the architecture, functionality, and operation of a possible implementation of the software for demand controller control logic  321 . In this regard, each block may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order noted in  FIG. 7 , or may include additional functions, without departing significantly from the functionality of the process whereby the customer premises demand controller  103  generates a shut off command. For example, two blocks shown in succession in  FIG. 7  may in fact be executed substantially concurrently, the blocks may sometimes be executed in the reverse order, or some of the blocks may not be executed in all instances, depending upon the functionality involved, as will be further clarified herein below. All such modifications and variations are intended to be included herein within the scope of this disclosure and to be protected by the accompanying claims. 
   The process starts at block  702 . At block  704 , micro-controller  301  executes demand controller control logic  321  residing in memory  320  to determine if any of the monitored parameters are outside of the defined range of values. At block  706 , if no parameters are outside of their defined range (the NO condition) the process returns back to block  704 . 
   At block  706 , once a monitored parameter is outside of the defined range (the YES condition), the process proceeds to block  708 . At block  708 , the micro-controller  301  correlates the deviation from the defined range with a plurality of predefined effects anticipated to produce a desired result. That is, the demand controller  103  compares the deviation of the monitored parameter against a plurality of predefined effects having a known energy demand decrease, thereby determining how much demand reduction is needed to offset the deviation. Due to the information extracted by the analog front end processor  330 , an additional embodiment of the demand controller  103  provides details relative to real time power factor, as well as peak vs. RMS current loads. This information would provide for a more fine tuned correlation in block  708  of  FIG. 7 . 
   At block  710 , the micro-controller  301  retrieves nominal demand from storage  310  in operational parameters  312  for each operating load and compares against the needed demand reduction. Micro-controller  301  then retrieves the unique address associated with the matching load from storage  310  in operational parameters  312 . 
   At block  712 , micro-controller  301  formulates the proper command structure for a shut off command to the load controllers  105  or  205  associated with the matching load. The command also includes the unique identifier of the specific relay associated with the matching load. Micro-controller  301 , via connection  306  to interface  302 , transmits the command to load controller  105  or  205 . 
   At block  714 , micro-controller  301  will set ‘temporary’ defined range(s) associated with the monitored parameter(s) that were initially out of range, as well as a duration of persistence. That is, the values used for a parameters defined range will be adjusted for a defined period of time to allow for the demand change to have an effect. Due to the monitoring of parameters on a cycle-by-cycle basis, this is required in order to alleviate a cascading response. The process then returns to block  704 . 
   In one embodiment of this control logic, the plurality of demand controllers  103  residing at the plurality of customer premises  104 , fed by a common customer premises transformer  101 , would be in communication with each other and thereby have access to the real time demand placed on the customer premises transformer  101  by each of the plurality of customer premises  104 . This information allows for the mathematical analysis of the primary side of the customer premises transformer  101 . Thus providing a more accurate definition of the out-of-range values for each of the monitored parameters. 
     FIG. 8  is a normalized real-world waveform ‘B’ shown in comparison to an ideal sinusoid ‘A’. This comparison emphasizes the variations seen between two waveforms that have the same amplitude and period. Real-world waveforms are in fact a composite of numerous waveforms having various amplitudes and periods. It is due to this fact that critical information about the energy delivery system can only be derived from a waveform analysis. Individual values that quantify a waveform, such as RMS, peak or period, cannot represent the many specific characteristics of an energy delivery system that may be over stressed. This ability to extract positional particular data in a waveform allows for customizable regions  801  that define areas of concern specific to the electricity supplier. These regions, along with their cause-and-effect, may be added to the list of monitored parameters which the demand controller  103  uses to determine the need for load shedding. Additionally, logged data, including waveforms, can be reviewed by the electricity supplier to assist in identifying delivery system strengths and weaknesses. 
   One skilled in the art will appreciate that demand controller  103  may be configured in an infinite number of operating modes to provide any desired degree of control and flexibility. A network of customer premises transformers  101 , each monitored by the plurality of intelligent demand controllers  103 , provides the electricity supplier with a system of self regulating loads that would follow the capabilities of the energy delivery system without undo inconvenience to the customer and minimal impact upon the electricity supplier&#39;s revenue stream. 
   It should be emphasized that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the accompanying claims.