Energy meter with onboard power quality analysis

Abstract

The present invention discloses an electric energy meter, which includes a plurality of first terminals for receiving the measured value of the current of each of one or more phases of electric power, and a plurality of second terminals for receiving the measured value of the voltage of each of the one or more phases of electric power. A controller is configured to analyze the measured value of the current and the measured value of the voltage of each of the one or more phases of electric power so as to detect power quality problems in one or more of the one or more phases of electric power. For each of the detected power quality problems, the controller is configured to determine whether the detected power quality problem is caused by a utility generating electric power or a consumer consuming electric power, and transmit a message indicating the detected power quality problem via a communication port operably coupled to the controller.

Description

Technical Field

[0001] The present disclosure relates generally to power systems and, more particularly, to power meters for monitoring energy delivered to such power systems. Background Art

[0002] Power systems are used to provide necessary power to various building systems such as, but not limited to, lighting systems, security systems, HVAC systems, and general power requirements. In some cases, energy meters are used to monitor the power system in order to detect potential problems with the power system. Energy meters are also used to measure power consumption for billing purposes. Various energy meters are known. Improvements in the use and functionality of energy meters would be desirable. Summary of the invention

[0003] The present disclosure relates generally to power systems, and more particularly to an energy meter for monitoring energy delivered to such power systems. A specific example of the present disclosure is an energy meter comprising a plurality of first terminals for receiving a measurement of a current of each of one or more phases of power delivered to a load; and a plurality of second terminals for receiving a measurement of a voltage of each of one or more phases of power delivered to the load. A controller is operably coupled to the plurality of first terminals and the plurality of second terminals, and is configured to analyze the measurement of the current and the measurement of the voltage of each of the one or more phases of power delivered to the load in order to determine a measurement of the cumulative power delivered to the load, and to determine one or more power quality issues (if any) in one or more of the one or more phases of power delivered to the load. A cumulative power register is operably coupled to the controller for storing the measurement of the cumulative power delivered to the load. A plurality of power quality monitoring registers are operably coupled to the controller. The controller is configured to save an indication of each of a plurality of different power quality issues in a corresponding one of the plurality of power quality monitoring registers. A communication port is operably coupled to the controller and configured to communicate with an external device. The controller is configured to transmit the measured value of the cumulative power delivered to the load and transmit an indication of each of one or more of the plurality of different power quality issues via the communication port.

[0004] Another example of the present disclosure is an energy meter, the energy meter including a plurality of terminals for receiving a measurement of power consumption of each of one or more phases of power delivered to a load. A controller is operably coupled to the plurality of terminals and is configured to analyze the measurement of power consumption of each of the one or more phases of power delivered to the load in order to determine a measurement of cumulative power delivered to the load, and to determine one or more power quality problems (if any) in the one or more phases of power delivered to the load. A cumulative power register is operably coupled to the controller for storing the measurement of cumulative power delivered to the load. A plurality of power quality monitoring registers are operably coupled to the controller, wherein the controller saves an indication of each of a plurality of different power quality problems in a corresponding one of the plurality of power quality monitoring registers. A communication port is operably coupled to the controller and is configured to communicate with an external device. The controller is configured to transmit the measurement of cumulative power delivered to the load and transmit an indication of each of one or more of the plurality of different power quality problems via the communication port.

[0005] Another example of the present disclosure is an energy meter, the energy meter comprising a plurality of first terminals for receiving a measurement of a current of each of one or more phases of power delivered to a load; and a plurality of second terminals for receiving a measurement of a voltage of each of one or more phases of power delivered to the load. A controller is operably coupled to the plurality of first terminals and the plurality of second terminals, and is configured to analyze the measurement of the current and the measurement of the voltage of each of the one or more phases of power delivered to the load in order to detect a power quality problem in one or more of the one or more phases of power delivered to the load. For each of the detected power quality problems, the controller is configured to determine whether the detected power quality problem is caused by a utility (i.e., a utility delivering the power) or a consumer (i.e., a consumer consuming the power), and transmit a message indicating the detected power quality problem via a communication port operably coupled to the controller.

[0006] The above summary is provided to facilitate understanding of some innovative features unique to the present disclosure, but is not intended to be a complete description. A comprehensive understanding of the present disclosure can be obtained by viewing the entire specification, claims, drawings and abstract as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure may be more fully understood by considering the following description of various examples in conjunction with the accompanying drawings, in which:

[0008] Figure 1 is a schematic block diagram of an exemplary energy meter;

[0009] Figure 2 It is shown that it can be used Figure 1 A schematic block diagram of an exemplary register of an exemplary energy meter;

[0010] Figure 3 It is shown Figure 1 A schematic block diagram of features of an exemplary energy meter;

[0011] Figure 4 It shows that Figure 1 A flowchart of an exemplary method performed by an exemplary energy meter of

[0012] Figure 5 It shows that Figure 1 Flowchart of an example method performed by an example energy meter.

[0013] Although the present disclosure is subject to various modifications and alternative forms, the details thereof have been shown by way of example in the accompanying drawings and will be described in detail. However, it should be understood that it is not intended to limit the present disclosure to the specific examples described. On the contrary, it is intended to cover all modifications, equivalents and alternatives that fall within the essence and scope of the present disclosure. DETAILED DESCRIPTION

[0014] The following description should be read with reference to the accompanying drawings, in which similar elements in different drawings are numbered in the same manner. The accompanying drawings are not necessarily drawn to scale, and they depict examples that are not intended to limit the scope of the present disclosure. Although examples of various elements are shown, those skilled in the art will recognize that many of the examples provided have suitable alternatives that can be utilized.

[0015] It is assumed herein that all numbers are modified by the term "about" unless the content clearly dictates otherwise. The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0016] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and / or" unless the content clearly dictates otherwise.

[0017] It should be noted that references to "one embodiment", "some embodiments", "other embodiments", etc. in the specification indicate that the described embodiments may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, these phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with one embodiment, it is contemplated that the feature, structure, or characteristic is described in conjunction with one embodiment, and it is contemplated that the feature, structure, or characteristic may be applied to other embodiments regardless of whether explicitly described, unless otherwise clearly stated.

[0018] The present disclosure as a whole relates to energy meters. The energy meters of the present disclosure can be used to measure and monitor the energy delivered to any number of different power consuming devices or loads. The energy meter can be configured to determine the amount and quality of the power delivered to the load. In some cases, the energy meter can be configured to measure the current and voltage delivered to the load so that the power utility can bill the consumer for the power it has used. In some cases, the energy meter can be considered a direct energy meter, which means that the energy meter is directly spliced ​​into the conductor that provides power to the load. In some cases, the energy meter can be considered an indirect energy meter or a CT (current transformer) energy meter, where the CT is used to provide an indication of the current flowing to the load and the line voltage tap is used to provide an indication of the voltage. It should be understood that many of the features discussed herein are equally applicable to direct energy meters and indirect or CT energy meters. In some cases, the energy meter of the present disclosure can provide a measurement of the power in each of the three phases in a three-phase power line.

[0019] Figure 1 1 is a schematic block diagram of an exemplary energy meter 10. In some cases, the energy meter 10 may be referred to as a power meter. The energy meter 10 may be configured to be installed at a consumer's location where electricity is consumed. The energy meter 10 may represent a direct energy meter or an indirect or CT energy meter, as described above. The exemplary energy meter 10 includes a plurality of terminals 12 that may be configured to receive measurements of power consumption of each of one or more phases of electricity delivered to a load. If the energy meter 10 is a direct meter, the plurality of terminals 12 may be configured to accommodate line input conductors and line output conductors, with the energy meter 10 disposed therebetween. If the energy meter 10 is an indirect meter, the plurality of terminals 12 may be configured to accommodate wires or cables that provide voltage measurements and wires or cables extending from a current transformer (CT), etc., which provide measurements of current delivered to the load.

[0020] In some cases, as will be discussed, the plurality of terminals 12 may be considered to be divided into one or more first terminals 14 and one or more second terminals 16. Although the one or more first terminals 14 are shown as including terminals 14a, 14b, and 14c, and the one or more second terminals 16 are shown as including terminals 16a, 16b, and 16c, it should be understood that this is merely exemplary. In some cases, the one or more first terminals 14 may include only one terminal or two terminals, or may include four or more terminals. Similarly, the one or more second terminals 16 may include only one terminal or two terminals, or may include four or more terminals. In some cases, when the energy meter 10 is an indirect or CT energy meter, the plurality of first terminals 14 may be configured to receive a measurement of the current of each of the one or more phases of the power delivered to the load, and the plurality of second terminals 16 may be configured to receive a measurement of the voltage of each of the one or more phases of the power delivered to the load.

[0021] The controller 18 can be operably coupled to a plurality of terminals 12, and can be configured, for example, to determine a plurality of power monitoring parameters based on a measurement of power consumption of each of one or more phases of power delivered to the load. In the example shown, the controller 18 is operably coupled to a communication port 20, so that the controller 18 can communicate with an external device 22. The external device 22 may represent a computing system associated with a utility generating the power quantified by the energy meter 10. The external device 22 may represent a computing system associated with an energy consumer, and the energy meter 10 may be located at the consumer's location. In some cases, the external device 22 may represent another power meter or a mesh network of power meters. The communication port 20 may be configured to adapt to a wired connection, such as, but not limited to, an Ethernet connection. The communication port 20 may be configured to adapt to a wireless protocol, such as, but not limited to, Bluetooth Low Energy (BLE), Zigbee, and / or WiFi, but other wireless protocols may also be considered.

[0022] As will be discussed in greater detail, controller 18 may be configured to determine an accumulation of electrical energy delivered and various reliability and / or quality characteristics of the electrical energy delivered. In some cases, controller 18 may be configured to transmit (e.g., via communication port 20) a measurement of the cumulative power delivered to the load and an indication of each of a plurality of different power quality issues. Controller 18 may be configured to analyze a measurement of the current of each of the phases of the power delivered to the load and a measurement of the voltage of each of one or more phases of the power delivered to the load, and determine a measurement of the cumulative power delivered to the load and determine one or more power quality issues in one or more phases of the power delivered to the load.

[0023] As will be understood, reliability refers to the availability of power, 24 hours a day, 7 days a week, and 365 days a year. Quality refers to deviations or distortions from a pure supply waveform and supply continuity. Any significant deviation in the magnitude, frequency, waveform, or symmetry of the line voltage can be considered a potential power quality problem. In order to be able to track and store these parameters, the exemplary energy meter 10 includes a plurality of power quality monitoring registers 24. The power quality monitoring registers 24 can be considered as addressable locations within the memory of the energy meter 10. The addressable locations can be static. In some cases, the addressable locations can be dynamic, meaning that the addressable locations in the memory can change according to changing memory requirements, or, for example, the power quality monitoring registers 24 require additional memory space.

[0024] In some cases, the plurality of power quality monitoring registers 24 may be considered to be divided into a plurality of first registers 26 and a plurality of second registers 28. Although the plurality of first registers 26 are shown as including registers 26a, 26b, and 26c, and the plurality of second registers 28 are shown as including registers 28a and 28b, it should be understood that this is merely illustrative. In some cases, the plurality of first registers 26 may include only one register, two registers, or three registers, or may include five or more registers. Similarly, the plurality of second registers 28 may include only one register, or may include three registers, four registers, or five or more registers. The energy meter 10 also includes a cumulative power register 30, which is operably coupled to the controller 18 and is configured to store a measurement of the cumulative power delivered to the consumer (sometimes over a period of time).

[0025] In some cases, the power meter 10 may include a user interface 32. The controller 18 may be configured to display, via the user interface 32, an indication of each of a plurality of different power quality issues that are collectively maintained in the plurality of power quality monitoring registers 24.

[0026] In some cases, the controller 18 may be configured to determine whether a particular power quality problem originates upstream of the power meter 10 (e.g., on the utility side) or downstream of the power meter 10 (e.g., on the consumer side). Power quality problems originating upstream of the power meter 10 may be attributed to the utility that provides the power delivered to the load. Power quality problems originating downstream of the power meter 10 may be attributed to the consumer of the power delivered to the load. Therefore, some of the power quality monitoring registers 24 may be used to track problems that originate upstream of the power meter 10 and may therefore be caused by the utility (or another consumer), and other power quality monitoring registers 24 may be used to track problems that are downstream of the power meter 10 and may therefore be caused by the consumer. In some cases, a plurality of first registers 26 may be assigned to track utility-related problems, and a plurality of second registers 28 may be assigned to track consumer-related problems.

[0027] The controller 18 may be configured to detect problems such as sags / swells, phase imbalance, short interruptions due to load, flicker due to load, harmonics, and frequency. The controller 18 may be configured to determine whether the utility or the consumer may be at fault for the particular problem detected. For example, the controller 18 may be configured to monitor the rate at which the current increases or decreases and the rate at which the voltage increases or decreases. If the current suddenly increases and the voltage decreases at the same time, the controller 18 may determine that the sag is caused by the consumer. If the current suddenly decreases and the voltage increases at the same time, the controller 18 may determine that the swell is caused by the consumer. If the current does not change and the voltage is experiencing a sag or swell, the controller 18 may determine that this is caused by the utility's distribution network.

[0028] In some cases, sags and swells can be divided into different categories, such as momentary, short-term and temporary, as shown in the following table. Here, "pu" means standard or reference voltage. In some countries and regions, the standard or reference voltage "pu" is 230 volts. In other countries and regions, the standard or reference voltage "pu" is 110 or 120 volts.

[0029]

[0030] In some cases, the controller 18 may be configured to monitor all three phases of the current in the three-phase power line. If the difference between the three phases exceeds a threshold, the controller 18 may determine that this is caused by the consumer. For short interruptions due to load and flicker due to load, the logic of sag / swell may also be extended to detect these. In some cases, PST (short term power) and PLT (long term power) may be calculated and compared to the change in current during the same time frame to determine whether the flicker is caused by the utility or the consumer. With respect to harmonics, the controller 18 may measure the current amplitude, the change in current amplitude, and any harmonics present, and compare to the harmonics of the voltage to determine whether the harmonics are caused by the utility or the consumer.

[0031] For frequency, the controller 18 may calculate and store an average frequency for the interval period. A change exceeding a certain threshold percentage (e.g., two percent) may cause the controller 18 to use a different register 26 to identify the energy during the period. It should be understood that frequency generally indicates a mismatch between supply and demand. If the frequency is above a specified frequency, this generally indicates that the supply is greater than the demand. If the frequency is below a specified frequency, this generally indicates that the supply is less than the demand. In some cases, and in some power generation systems, the specified frequency may be 50 Hertz (Hz). In some power generation systems, the specified frequency may be different. For example, in the United States, the specified threshold is 60 Hz.

[0032] Figure 2 is a schematic block diagram showing an exemplary register 40 that may be used with the energy meter 10. The register 40 may be considered an example of a power quality monitoring register 24. In the example shown, the register 40 is divided into a set of registers 42 that are dedicated to issues related to a utility (or otherwise upstream of the energy meter 10), and a set of registers 44 that are dedicated to issues related to a consumer (or otherwise downstream of the energy meter 10). For example, the set of registers 42 may be considered to represent a plurality of first registers 26, while the set of registers 44 may be considered to represent a plurality of second registers 28.

[0033] The set of registers 42 includes a register 42a labeled R1: Sag / Swell, a register 42b labeled R2: Phase Unbalance, a register 42c labeled R3: Short Interruption, a register 42d labeled R4: Flicker, and a register 42e labeled R5: Harmonics. When the controller 18 detects a power quality problem associated with one of these categories and assigned to the utility, the controller 18 stores an indication of the power quality problem in the appropriate register 42. The set of registers 44 includes a register 44a labeled Ra: Frequency, and a register 44b labeled Rb: Sags and Swells Due to Supply. When the controller 18 detects a power quality problem associated with one of these categories and assigned to a consumer, the controller 18 stores an indication of the power quality problem in the appropriate register 44. Each register may store a value or set of values ​​representing the accumulation of power delivered to the consumer and the corresponding power quality problem. The cumulative power register 30 may store a value or set of values ​​representing the accumulation of the total power delivered to the load.

[0034] Figure 3 1 is a schematic block diagram illustrating an architecture 50 that may be employed within the energy meter 10. The measured values ​​of current and voltage as indicated at block 52 are provided to an attenuation block 54, if desired. The attenuated current and voltage values ​​are provided to an ADC (analog-to-digital converter) block 56 and then to a metering engine 58, 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 block 60, where PQM (power quality measurement) parameter types are detected in the monitored power. PQM parameter types may include, for example, sags / swells, phase imbalance, short interruptions due to load, flicker due to load, harmonics, and frequency.

[0035] Block 64 provides the PQM configuration values ​​to block 66, which stores, determines, or otherwise determines a particular threshold for flagging certain of the PQM parameter types as power quality issues. Block 66 provides the threshold to block 68. Block 68 uses the threshold to identify which of the detected PQM parameter types identified by block 60 do not meet the corresponding threshold. Depending on the detected PQM type that fails to meet the corresponding threshold, block 70 asserts a flag corresponding to the corresponding PQM registers R1 to R5 and Ra and Rb. In this example, the PQM registers R1 to R5 and Ra and Rb may correspond to Figure 2The block 62 includes the PQM registers R1 to R5 and Ra and Rb and is configured to monitor the flag asserted by the block 70 to determine which, if any, of the PQM registers R1 to R5 and Ra and Rb should start and stop accumulating the power measured by the metering engine 58. Each of the PQM registers R1 to R5 and Ra and Rb may store a value or set of values ​​representing the accumulation of power delivered to the consumer and the corresponding power quality issues. The accumulated values ​​or sets of values ​​in the PQM registers R1 to R5 and Ra and Rb may be saved to a memory via the block 72.

[0036] Figure 4 8 is a flow chart showing an exemplary method 80 that may be performed by the energy meter 10. As indicated at block 82, a type of harmonic is measured. As indicated at block 84, the energy value is recorded in a normal energy register (such as the cumulative power register 30). A determination is made (such as by the controller 18) as to whether the measured harmonic is greater than a threshold. If not, control returns to block 82. If so, control passes to block 88 and the order of the harmonic is identified. The amount of energy delivered to the consumer when the measured harmonic is greater than the threshold is accumulated in an R5 register (such as register 42e), as indicated at block 90.

[0037] Figure 5 1 is a flow chart showing an exemplary method 100 that may be performed by the energy meter 10. The frequency is measured and the average frequency is calculated, as indicated at block 102. As indicated at block 104, the energy value is recorded in a normal energy register (such as the cumulative power register 30). A determination is made (such as by the controller 18) as to whether the current frequency differs from the average frequency by more than two percent. If not, control returns to block 102. If so, control passes to block 108, and the amount of energy delivered to the consumer when the current frequency differs from the average frequency by more than two percent is accumulated in a Ra register (such as register 44a), as indicated at block 108.

[0038] Although several illustrative embodiments of the present disclosure have been described in this manner, it will be readily understood by those skilled in the art that other embodiments may be made and used within the scope of the claims appended hereto. However, it should be understood that the present disclosure is in many respects merely illustrative. Details (especially details related to shape, size, arrangement of parts, and exclusion and order of steps) may be changed without exceeding the scope of the present disclosure. Of course, the scope of the present disclosure is defined in the language of the appended claims.

Claims

1. An electric energy meter, include: a plurality of first terminals for receiving measurements of current for each of one or more phases of power delivered to a load; a plurality of second terminals for receiving measurements of a voltage of each of one or more phases of power delivered to the load; a controller operably coupled to the plurality of first terminals and the plurality of second terminals, the controller configured to analyze the measured values ​​of the current and the measured values ​​of the voltage of each of the one or more phases of power delivered to the load to: determining a measure of cumulative power delivered to the load; as well as determining one or more power quality problems in one or more of the one or more phases of power delivered to the load; a cumulative power register operatively coupled to the controller for storing the measurement of cumulative power delivered to the load; a plurality of power quality monitoring registers operably coupled to the controller, the controller storing an indication of each of a plurality of different power quality problems in a corresponding one of the plurality of power quality monitoring registers, wherein the indication includes a measurement representing a cumulative power delivered to a load and a value or set of values ​​for the corresponding power quality problem; and a communications port operably coupled to the controller and configured to communicate with an external device, the controller configured to transmit the measurement of the cumulative power delivered to the load and to transmit an indication of each of one or more of the plurality of different power quality issues via the communications port, wherein the controller is further configured to determine whether a particular power quality problem originates upstream of the energy meter or downstream of the energy meter, The multiple power quality monitoring registers include a first group of power quality monitoring registers, each of which corresponds to a different power quality problem originating upstream of the power meter; and a second group of power quality monitoring registers, each of which corresponds to a different power quality problem originating downstream of the power meter.

2. The power meter of claim 1 , wherein the power quality issues originating upstream of the power meter are attributed to a utility providing the power delivered to the load, and the power quality issues originating downstream of the power meter are attributed to a consumer of the power delivered to the load. 3 . The energy meter of claim 1 , wherein the external device comprises a computing device at a location of a consumer and / or a computing device of a utility providing the power delivered to the load. 4 . The energy meter of claim 1 , wherein the energy meter is configured to detect a sag / swell in one or more phases of power delivered to the load and / or a phase imbalance in power delivered to the load. 5 . The energy meter of claim 1 , wherein the energy meter is configured to detect a short interruption of power delivered to the load and / or a flicker of power delivered to the load. The power meter of claim 1 , wherein the power meter is configured to detect one or more harmonics of power delivered to the load. 7 . The power meter of claim 1 , wherein the power meter is configured to detect a frequency of power delivered to the load.

8. The energy meter of claim 1, wherein the communication port comprises a wireless communication port.

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