Patent Description:
Power systems are used to provide necessary power to a wide variety of building systems such as but not limited to lighting systems, security systems, HVAC systems and general power requirements. In some cases, electric energy meters are used to monitor a power system in order to detect potential problems with the power system. Electric energy meters are also used to measure power consumption for billing purposes. A variety of electric energy meters are known. Improvements in the use and functionality of electric energy meters would be desirable.

Examples of currently used systems can be found in the following:
<CIT>, which discloses an electronic meter which automatically detects the service type and voltage to which the meter is installed and which either automatically configures its own programming to the detected service is disclosed. An electronic energy meter that permits the addition of new measurements or testing capabilities without requiring factory modifications to effect such functionality changes is also disclosed. The meter includes firmware which measures the characteristics of electrical energy supplied to the meter and which generates characteristic signals reflective of the measured characteristics of the electrical energy. A processor is connected to receive and process the characteristic signals. The processing of the characteristic signals includes selecting and manipulating certain of the characteristic signals and generating characteristic information in response to the selection and generating additional characteristic information in response to the manipulation. It is preferred for the meter to include a memory having reference information stored therein. In such an embodiment, the manipulation of characteristic signals includes retrieving certain of the reference information and generating the characteristic information in response to the selected signals and the reference information.

<CIT>, which discloses a power quality detection, monitoring, reporting, recording and communication in a revenue accuracy electrical power meter. Wherein transient events are detected by monitoring the wave shape of the electrical power and comparing deviations to a known threshold. Sags and Swells are detected by computing root mean square value over a rolling window and comparing the computed value with a known threshold. Harmonic frequencies and symmetrical components are quantified by a known algorithm and compared with a known threshold. Incoming waveforms are stored to memory. All recorded and computed data is moved to non-volatile storage via direct memory access transfer in the event that a power quality event jeopardizes the operating power of the meter. Further, the meter provides a power supply utilizing high and low capacitive storage banks to supply sufficient energy to survive short duration power quality events which jeopardize the meter's operating power.

<CIT>, which discloses an intelligent electronic device IED has enhanced power quality and communications capabilities. The IED can perform energy analysis by waveform capture, detect transient on the front-end voltage input channels and provide revenue measurements. The IED splits and distributes the front-end input channels into separate circuits for scaling and processing by dedicated processors for specific applications by the IED. Front-end voltage input channels are split and distributed into separate circuits for transient detection, waveform capture analysis and revenue measurement, respectively. Front-end current channels are split and distributed into separate circuits for waveform capture analysis and revenue measurement, respectively.

<CIT>, which discloses a method that comprises detecting a power quality event, determining if one or more power outages occur in a defined time period extending from a beginning of the power quality event to an end of the power quality event and if one or more power outages occurs in the defined time period, then performing an analysis, where performing the analysis comprises determining if the one or more power outages is associated with the power quality event. The method may also comprise outputting the information regarding the analysis to a display device.

The present disclosure relates generally to power systems and more particularly to electric energy meters used for monitoring delivered energy to such power systems. An electric energy meter according to the invention is defined in independent claim <NUM>.

The preceding summary is provided to facilitate an understanding of some of the innovative features unique to the present disclosure and is not intended to be a full description. A full appreciation of the disclosure can be gained by taking the entire specification, claims, figures, and abstract as a whole.

The disclosure may be more completely understood in consideration of the following description of various examples in connection with the accompanying drawings, in which:.

It should be understood, however, that the intention is not to limit the disclosure to the particular examples described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

The following description should be read with reference to the drawings, in which like elements in different drawings are numbered in like fashion. The drawings, which are not necessarily to scale, depict examples that are not intended to limit the scope of the disclosure. Although examples are illustrated for the various elements, those skilled in the art will recognize that many of the examples provided have suitable alternatives that may be utilized.

It is noted that references in the specification to "an embodiment", "some embodiments", "other embodiments", etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is contemplated that the feature, structure, or characteristic is described in connection with an embodiment, it is contemplated that the feature, structure, or characteristic may be applied to other embodiments whether or not explicitly described unless clearly stated to the contrary.

The disclosure generally pertains to electric energy meters. Electric energy meters of the present disclosure may be used to measure and monitor energy that is delivered to any number of different power consumption devices, or loads. The electric energy meters may be configured to determine the quantity and quality of the power being delivered to the load. In some cases, the electric energy meters may be configured to measure the current and voltage being delivered to a load such that a power utility can bill a consumer for the power they have used. In some cases, an electric energy meter may be considered as being a direct electric energy meter, meaning that the electric energy meter is directly spliced into a conductor providing power to the load. In some instances, the electric energy meter may be considered as being an indirect electric energy meter or a CT (current transformer) electric energy meter in which a CT is used to provide an indication of current flowing to a load and a line voltage tap is used to provide an indication of the voltage. It will be appreciated that many of the features discussed herein are equally applicable to direct electric energy meters and to indirect or CT electric energy meters. In some cases, the electric energy meters of the present disclosure may provide a measure of power in each of the three phases in a three-phase power line.

<FIG> is a schematic block diagram of an illustrative electric energy meter <NUM>. In some cases, the electric energy meter <NUM> may be referred to as a power meter. The electric energy meter <NUM> may be configured to be installed at a consumer's location, where the power is being consumed. The electric energy meter <NUM> may represent a direct electric energy meter or an indirect or CT electric energy meter, as noted above. The illustrative electric energy meter <NUM> includes a plurality of terminals <NUM> that may be configured for receiving a measure of power consumption for each of one or more phases of power that is delivered to a load. If the electric energy meter <NUM> is a direct meter, the plurality of terminals <NUM> may be configured to accommodate a LINE IN conductor and a LINE out conductor, with the electric energy meter <NUM> disposed therebetween. If the electric energy meter <NUM> is an indirect meter, the plurality of terminals <NUM> may be configured to accommodate a wire or cable providing a measure of voltage as well as wires or cables extending from a current transformer (CT) or the like that provides a measure of current passing to the load.

In some cases, as will be discussed, the plurality of terminals <NUM> may be considered as being divided into a one or more first terminals <NUM> and a one or more second terminals <NUM>. While the one or more first terminals <NUM> is shown as including a terminal 14a, a terminal 14b and a terminal 14c, and the one or more second terminals <NUM> is shown as including a terminal 16a, a terminal 16b and a terminal 16c, it will be appreciated that this is merely illustrative. In some cases, the one or more first terminals <NUM> may only include one terminal or two terminals, or may include four or more terminals. Similarly, the one or more second terminals <NUM> may include only one terminal or two terminals, or may include four or more terminals. In some cases, when the electric energy meter <NUM> is an indirect or CT electric energy meter, the plurality of first terminals <NUM> may be configured for receiving a measure of current of each of one or more phases of power that is delivered to the load and the plurality of second terminals <NUM> may be configured for receiving a measure of voltage of each of the one or more phases of power that is delivered to the load.

A controller <NUM> may be operably coupled to the plurality of terminals <NUM> and may for example be configured to determine a number of power monitor parameters based on the measure of power consumption for each of one or more phases of power that is delivered to the load. In the example shown, the controller <NUM> is operably coupled to a communication port <NUM>, such that the controller <NUM> is able to communicate with an external device <NUM>. The external device <NUM> may represent a computing system associated with a utility generating the electricity being quantified by the electric energy meter <NUM>. The external device <NUM> may represent a computing system associated with a consumer of the electrical energy, and the electric energy meter <NUM> may be located at the consumer's location. In some cases, the external device <NUM> may represent another electric power meter, or a mesh network of electric power meters. The communication port <NUM> may be configured to accommodate a wired connection such as but not limited to an Ethernet connection. The communication port <NUM> may be configured to accommodate a wireless protocol such as but not limited to Bluetooth Low Energy (BLE), Zigbee, and/or WiFi, although other wireless protocols are also contemplated.

As will be discussed in greater detail, the controller <NUM> may be configured to ascertain an accumulation of electrical energy delivered as well as various reliability and/or quality characteristics of the delivered electrical energy. In some cases, the controller <NUM> may be configured to communicate (e.g. via communication port <NUM>) a measure of accumulated power delivered to the load as well as an indication of each of one or more of a plurality of different power quality issues. The controller <NUM> may be configured to analyze the measure of current of each of the phases of power delivered to the load and the measure of voltage of each of the one or more phases of power delivered to the load and determine a measure of accumulated power delivered to the load and to determine one or more power quality issues in one or more of the one or more phases of power that is delivered to the load.

As will be appreciated, reliability refers to the availability of the power supply, <NUM> hours per day, <NUM> days per week, <NUM> days per year. Quality refers to deviations or distortions from a pure supply waveform and continuity of supply. Any significant deviation in the magnitude, frequency, waveform or symmetry of line voltages may be considered as being a potential power quality issue. In order to be able to track and store these parameters, the illustrative electric energy meter <NUM> includes a plurality of power quality monitor registers <NUM>. The power quality monitor registers <NUM> may be considered as being addressable locations within a memory of the electric energy meter <NUM>. The addressable locations may be static. In some cases, the addressable locations may be dynamic, meaning that the addressable locations in memory may change in accordance with changing memory needs, or which power quality monitor registers <NUM> need additional memory space, for example.

In some cases, the plurality of power quality monitor registers <NUM> may be considered as being divided into a number of first registers <NUM> and a number of second registers <NUM>. While the number of first registers <NUM> is shown as including a register 26a, a register 26b and a register 26c, and the number of second registers <NUM> is shown as including a register 28a and a register 28b, it will be appreciated that this is merely illustrative. In some cases, the number of first registers <NUM> may include only one register, two registers or three registers, or may include five or more registers. Similarly, the number of second registers <NUM> may include only one register, or may include three registers, four registers or five or more registers. The electric energy meter <NUM> also includes an accumulated power register <NUM> that is operably coupled with the controller <NUM> and that is configured to store a measure of accumulated power delivered to the consumer, sometimes over a period of time.

In some cases, the electric energy meter <NUM> may include a user interface <NUM>. The controller <NUM> may be configured to display the indications of each of a plurality of different power quality issues that are collectively saved in the plurality of power quality monitor registers <NUM> via the user interface <NUM>.

In some cases, the controller <NUM> may be configured to determine whether a particular power quality issue originated upstream of the electric energy meter <NUM> (e.g. utility side) or downstream (e.g. consumer side) of the electric energy meter <NUM>. Power quality issues originating upstream of the electric energy meter <NUM> may be attributed to a utility that provides the power that is delivered to the load. Power quality issues originating downstream of the electric energy meter <NUM> may be attributed to a consumer of the power that is delivered to the load. Accordingly, some of the power quality monitor registers <NUM> may be used for tracking problems that originated upstream of the electric energy meter <NUM>, and thus possibly caused by the utility (or another consumer) and others of the power quality monitor registers <NUM> may be used for tracking problems that are downstream of the electric energy meter <NUM> and thus possibly caused by the consumer. In some cases, the number of first registers <NUM> may be assigned to tracking utility-related problems and the number of second registers <NUM> may be assigned to tracking consumer-related problems.

The controller <NUM> may be configured to detect problems such as sag/swell, phase unbalance, short interruptions due to load, flickering due to load, harmonics and frequency. The controller <NUM> may be configured to ascertain whether the utility or the consumer may be at fault for the particular problems detected. For example, the controller <NUM> may be configured to monitor how quickly current is increasing or decreasing as well as how quickly voltage is increasing or decreasing. If the current is increasing suddenly while at the same time voltage is dropping, the controller <NUM> may determine that this sag is caused by the consumer. If the current is decreasing suddenly while at the same time voltage is increasing, the controller <NUM> may determine that this swell is caused by the consumer. If the current is unchanging while the voltage is undergoing either sag or swell, the controller <NUM> may determine that this being caused by the utility's distribution network.

In some cases, sag and swell may be divided into different categories such as instantaneous, momentary and temporary, as indicated in the table below. In this, "pu" represents a standard or reference voltage. In some countries and regions, the standard or reference voltage "pu" is <NUM> volts. In other countries and regions, the standard or reference voltage "pu" is <NUM> or <NUM> volts.

In some cases, the controller <NUM> may be configured to monitor all three phases of the current in a three-phase power line. If differences between the three phases exceeds a threshold, then the controller <NUM> may determine that this is caused by the consumer. For short interruptions due to loads and flickering due to loads, the logic of sag/swell can be extended to detect these as well. In some cases, PST (power short term) and PLT (power long term) can be calculated and compared with changes in current during the same time frame in order to determine if a flickering is caused by the utility or by the consumer. With respect to harmonics, the controller <NUM> may measure the current amplitude, change in current amplitude and any harmonics present and compare to the harmonics in voltage to determine whether the harmonics are being caused by the utility or by the consumer.

For frequency, the controller <NUM> may calculate and store average frequencies for an interval period. A variation of more than some threshold percent (e.g. two percent) may cause the controller <NUM> to identify the energy during that period using a different register <NUM>. It will be appreciated that frequency typically indicates a mismatch between supply and demand. If the frequency is above a designated frequency, this often indicates that supply is greater than demand. If the frequency is below the designated frequency, this often indicates that supply is less than demand. In some cases, and in some power generation systems, the designated frequency may be <NUM> Hertz (Hz). In some power generation systems, the designated frequency may be different. For example, in the United States, the designated threshold is <NUM>.

<FIG> is a schematic block diagram showing illustrative registers <NUM> that may be used in the electric energy meter <NUM>. The registers <NUM> may be considered as an example of the power quality monitor registers <NUM>. In the example shown, the registers <NUM> are divided into a set of registers <NUM> that are dedicated to issues relating to the utility (or otherwise upstream of the electric energy meter <NUM>) and a set of registers <NUM> that are dedicated to issues relating to the consumer (or otherwise downstream of the electric energy meter <NUM>). The set of registers <NUM> may be considered as representative of the number of first registers <NUM> while the set of registers <NUM> may be considered as representative of the number of second registers <NUM>, for example.

The set of registers <NUM> includes a register 42a that is labeled R1: Sag/Swell, a register 42b that is labeled R2:Phase Unbalance, a register 42c that is labeled R3: Short Interruption, a register 42d that is labeled R4:Flickering and a register 42e that is labeled R5:Harmonics. When the controller <NUM> detects a power quality issue pertaining to one of these categories and is assigned to the utility, the controller <NUM> will store an indication of the power quality issue in the appropriate register <NUM>. The set of registers <NUM> includes a register 44a that is labeled Ra: Frequency and a register 44b that is labeled Rb: Sag/swell due to supply. When the controller <NUM> detects a power quality issues pertaining to one of these categories and assigned to the consumer, the controller <NUM> will store an indication of the power quality issue in the appropriate register <NUM>. Each register stores a value or set of values that represent an accumulation of power that was delivered to the consumer with the corresponding power quality issue. The accumulated power register <NUM> may store a value or set of values that represent an accumulation of total power delivered to the load.

<FIG> is a schematic block diagram showing an architecture <NUM> that may be employed within the electric energy meter <NUM>. Measurements of current and voltage, as indicated at block <NUM>, are provided to an attenuation block <NUM> for attenuation if needed. The attenuated current and voltage values are provided to an ADC (analog to digital converter) block <NUM> and then to a Metrology engine <NUM>, which may update a value or set of values in an accumulated power register to represent the accumulation of power delivered to the consumer. From there, control passes to a block <NUM>, where PQM (power quality measurement) parameter types are detected in the monitored power. The PQM parameter types may include, for example, sag/swell, phase unbalance, short interruptions due to load, flickering due to load, harmonics and frequency.

Block <NUM> provides PQM configuration values to block <NUM>, which stores, determines or otherwise ascertains particular threshold values for flagging certain ones of the PQM parameter types as power quality issues. Block <NUM> provides the thresholds values to a block <NUM>. Block <NUM> uses the thresholds to identifies which of the detected PQM parameter types identified by block <NUM> do not meet the corresponding threshold. Depending on the detected PQM types that failed to meet the corresponding threshold, block <NUM> asserts a flag that corresponds to a corresponding PQM register R1 to R5 and Ra and Rb. In this example, PQM registers R1 to R5 and Ra and Rb may correspond to registers 42a-42e and 44a-44b of <FIG>. Block <NUM> include PQM registers R1 to R5 and Ra and Rb, and is configured to monitor the flags asserted by block <NUM> to determine which if any of the PQM registers R1 to R5 and Ra and Rb should start and stop accumulating power measured by the metrology engine <NUM>. Each PQM register R1 to R5 and Ra and Rb may store a value or set of values that represent an accumulation of power that was delivered to the consumer with the corresponding power quality issue. The accumulated value or set of values in PQM registers R1 to R5 and Ra and Rb may be save to memory via block <NUM>.

<FIG> is a flow diagram showing an illustrative method <NUM> that may be carried out by the electric energy meter <NUM>. A type of harmonic is measured, as indicated at block <NUM>. The energy value is recorded in the normal energy register (such as the accumulated power register <NUM>), as indicated at block <NUM>. A determination is made (such as by the controller <NUM>) as to whether the measured harmonic is greater than a threshold. If not, control reverts to block <NUM>. If so, control passes to block <NUM> and the order of the harmonic is identified. An amount of energy that is delivered to the consumer while the measured harmonic is greater than the threshold is accumulated in R5 register (such as the register 42e), as indicated at block <NUM>.

<FIG> is a flow diagram showing an illustrative method <NUM> that may be carried out by the electric energy meter <NUM>. Frequency is measured and average frequency is calculated, as indicated at block <NUM>. The energy value is recorded in the normal energy register (such as the accumulated power register <NUM>), as indicated at block <NUM>. A determination is made (such as by the controller <NUM>) as to whether the current frequency differs from the average frequency by greater than two percent. If not, control reverts to block <NUM>. If so, control passes to block <NUM>, and an amount of energy that is delivered to the consumer while the current frequency differs from the average frequency by greater than two percent is accumulated in Ra register (such as the register 44a), as indicated at block <NUM>.

Claim 1:
An electric energy meter (<NUM>), comprising:
a plurality of first terminals (<NUM>) for receiving a measure of current of each of one or more phases of power that is delivered to a load;
a plurality of second terminals (<NUM>) for receiving a measure of voltage of each of one or more phases of power that is delivered to the load;
a controller (<NUM>) operatively coupled to the plurality of first terminals (<NUM>) and the plurality of second terminals (<NUM>), the controller (<NUM>) configured to analyze the measure of current and the measure of voltage of each of the one or more phases of power that is delivered to the load to:
determine a measure of accumulated power delivered to the load; and
determine one or more power quality issues in one or more of the one or more phases of power that is delivered to the load;
an accumulated power register operatively coupled to the controller (<NUM>) for storing the measure of accumulated power delivered to the load;
a plurality of power quality monitor registers (<NUM>) operably coupled to the controller (<NUM>), the controller saving indications of each of a plurality of different power quality issues in a corresponding one of the plurality of power quality monitor registers (<NUM>), wherein the indications include a value or a set of values that represent the measure of accumulated power delivered to the load with the corresponding power quality issue; and
a communication port (<NUM>) operably coupled to the controller (<NUM>) and configured to communicate with an external device (<NUM>), the controller (<NUM>) configured to communicate the measure of accumulated power delivered to the load and communicate an indication of each of one or more of the plurality of different power quality issues via the communication port (<NUM>),
characterised in that
the controller is further configured to ascertain whether a particular power quality issue originated upstream of the electric energy meter or downstream of the electric energy meter (<NUM>), wherein the plurality of power quality monitor registers (<NUM>) comprises a first set of power quality monitor registers (<NUM>) that each correspond to the different power quality issue originating upstream of the electric energy meter (<NUM>), and a second set of power quality monitor registers (<NUM>) that each correspond to the different power quality issue originating downstream of the electric energy meter (<NUM>).