Power usage in a power distribution device for multiple electrical loads

Abstract

According to an aspect of the application, there is provided a method of estimating power usage in an electrical distribution apparatus for a plurality of electrical loads, the electrical distribution apparatus comprising an electrical circuit comprising a plurality of branch circuits arranged in parallel, each branch circuit coupled to one or more of the plurality of electrical loads, the electrical distribution apparatus configured to distribute power received from a power supply via a supply line across the electrical circuit, the method comprising: measuring a voltage across at least one of the plurality of branch circuits; measuring a current in a monitored branch circuit of the plurality of branch circuits; and detecting a first type of load change event if there is a change in the measured current and a corresponding change in the measured voltage, wherein the change in the measured current and the corresponding change in the measured voltage correspond to a change in load on the electrical circuit provided by one or more of the electrical loads in the monitored branch circuit; estimating a line impedance in the supply line in dependence on detecting the first type of load change event, wherein the estimate of the line impedance is based on the change in the measured current and the change in the measured voltage corresponding to the detected first type of load change event; and estimating a total power usage of the electrical circuit based on: a voltage of the power supply; the measured voltage; and the estimate of the line impedance.

Description

Technical Field

[0001] This disclosure relates throughout to a method for determining the electrical power consumption of electrical appliances in a building using a building's power distribution system. Various aspects of this disclosure relate to methods and control systems for power distribution systems. Background Technology

[0002] Typically, a building includes electrical distribution equipment, such as a switchboard, which is configured to distribute power supply to the building's various circuits and appliances. The distribution equipment usually receives power from a local transformer connected to the distribution network via a service inlet. In this way, the service inlet forms the power supply line between the distribution network and the distribution equipment.

[0003] A power distribution unit includes or is connected to multiple sub-circuits (referred to as branch circuits) arranged in parallel to provide electrical connections to electrical appliances in a building. Each branch circuit unit is electrically connected to one or more electrical appliances, and the power distribution unit includes protective fuses or circuit breakers for each branch circuit within a common enclosure.

[0004] An appliance in an operating electrical system generates a demand for electricity, known as an electrical load. The power distribution system is configured to meet these diverse demands within a building by distributing power supply among branch circuits according to the corresponding electrical load in each branch circuit. In this way, an appropriate power supply can be provided to power each appliance in the building's electrical system.

[0005] A power distribution device is known, comprising multiple current sensors and voltage sensors for determining the power consumption of electrical appliances. Using such a power distribution device, it is known that the total power consumption of electrical appliances in a building can be estimated by aggregating the power measurements of branch circuits. Summary of the Invention

[0006] According to one aspect of this disclosure, a method is provided for estimating power usage in a power distribution device for multiple electrical loads, the power distribution device including a circuit comprising a plurality of branch circuits arranged in parallel, each branch circuit coupled to one or more of the plurality of electrical loads, the power distribution device being configured to distribute power received from a power supply via a power supply line across the circuit, the method comprising: measuring a voltage across at least one of the plurality of branch circuits; and estimating the total power usage in the circuit based on: the voltage of the power supply; the measured voltage; and an estimate of the line impedance in the power supply line.

[0007] According to another aspect of this disclosure, a method is provided for estimating power usage in a power distribution unit (in a building) comprising multiple electrical loads. The power distribution unit includes a circuit comprising multiple branch circuits arranged in parallel. Each branch circuit is coupled to one or more of the multiple electrical loads. The power distribution unit is configured to distribute power received from a power supply via a power supply line across the circuit. The method includes: measuring a voltage across at least one of the multiple branch circuits; measuring a current in a monitored branch circuit among the multiple branch circuits; and detecting a first type of load change event if a change in the measured current and a corresponding change in the measured voltage exist, wherein the change in the measured current and the corresponding change in the measured voltage correspond to a change in load on the circuit supplied by one or more electrical loads in the monitored branch circuit; estimating a line impedance in the power supply line based on the detected first type of load change event, wherein the estimation of the line impedance is based on the measured change in current and the measured change in voltage corresponding to the detected first type of load change event; and estimating the total power usage of the circuit based on: the voltage of the power supply; the measured voltage; and the estimation of the line impedance.

[0008] In this way, the total power consumption of the circuit can be determined without measuring the current in each branch circuit. Advantageously, this reduces the need for current sensors in each branch circuit, which can reduce hardware complexity and cost.

[0009] The power supply received via the power supply line can be an alternating power supply with amplitude and frequency. Therefore, the measured current can form an alternating current waveform with peaks and troughs. Similarly, the measured voltage can form an alternating voltage waveform with corresponding peaks and troughs.

[0010] An estimate of line impedance can be an estimate of the effective resistance (i.e., impedance) of the alternating current in the power supply line, which can be caused by, for example, the combined effect of ohmic resistance and reactance.

[0011] The first type of load change event can also be referred to as a 'monitored load change event'. In this case, if there is a (suitable) increase or decrease in the amplitude of the measured current between consecutive peaks or consecutive peaks and troughs in the measured current, the change in the measured current can correspond to a change or step change in the load on the circuit provided by one or more electrical loads in the monitored branch circuit. For example, the increase or decrease in the amplitude of the measured current can be greater than 5% of the amplitude of the measured current.

[0012] If there is a decrease or increase (step or other suitable) in the amplitude of the measured voltage between consecutive peaks or between consecutive peaks and troughs, the corresponding change in the measured voltage can correspond to a change in the load on the circuit provided by one or more electrical loads in the monitored branch circuit. The change or step change in the measured voltage can occur simultaneously with a change in the measured current, or during the time period corresponding to the change in the measured current. For example, a significant increase or decrease in the amplitude of the measured voltage can be greater than 5% of the amplitude of the measured voltage.

[0013] Therefore, the first type of load change event can be detected based on the changes between consecutive peaks or between consecutive peaks and troughs in the measured current. Additionally, the first type of load change event can be detected based on the changes between consecutive peaks or between consecutive peaks and troughs in the measured voltage.

[0014] In one example, for a first-type load change event, the measured current change exceeds a current threshold change. In other words, for the first-type load change event to be detected, there must be a corresponding change in the measured current that exceeds the current threshold change. For example, a current threshold change can be defined for the measured current change between consecutive peaks or consecutive peaks and troughs in the measured current. Alternatively, the current threshold change can be defined within a specified time period. The specified time period can correspond to the time it takes for the current in each branch of the circuit to stabilize after a load change in the circuit supplied by one or more electrical loads.

[0015] The threshold change of current can be configured, for example, to exceed: any change in the measured current originating from the power supply; and any change in the measured current corresponds to a change in the load on the circuit provided by one or more electrical loads in any branch circuit other than the monitored branch circuit. In this way, the change in the measured current is effectively calibrated, and such a change will not be erroneously detected as a first-type load change event.

[0016] Alternatively, the estimate of the line impedance RL can be determined according to the following equation:

[0017]

[0018] Where RL is the estimated line impedance in the power supply line; ΔV1 is the measured voltage change corresponding to the detected first type of load change event; and ΔI1 is the measured current change corresponding to the detected first type of load change event. Advantageously, in this way, an estimate of the line impedance RL can be determined based on the measured changes in the monitored branch circuit without requiring measurements in other branch circuits. In one example, ΔV1 can take the form of a change or a step change between consecutive peaks or between consecutive peaks and troughs in the measured voltage corresponding to the detected first type of load change event. For example, ΔI1 can take the form of a change or a step change between consecutive peaks or between consecutive peaks and troughs in the measured current corresponding to the detected first type of load change event.

[0019] In one example, the method includes re-estimating the line impedance if: a first-type additional load change event is detected; and the measured voltage associated with the first-type additional load change event is greater than the measured voltage associated with the load change event on which the current estimate of the line impedance is based. The re-estimation of the line impedance is based on the measured changes in current and voltage corresponding to the first-type additional load change event. In this way, the estimate of the line impedance is determined based on the measured changes in current and voltage when the total electrical load of multiple electrical loads is minimized, and therefore, the estimate of the line impedance is most accurate.

[0020] Optionally, the method includes detecting a second type of load change event if there is a change in the measured voltage corresponding to a change in the load on a circuit supplied by one or more electrical loads among a plurality of electrical loads. The second type of load change event may also be referred to as an 'unmonitored load change event' or 'uncontrolled load change event'. The measured voltage may correspond to a change in the load on a circuit supplied by one or more electrical loads among a plurality of electrical loads if there is a suitable increase or decrease in the amplitude of the measured voltage between consecutive peaks, or between consecutive peaks and troughs. For example, the increase or decrease in the amplitude of the measured voltage may be greater than 5% of the amplitude of the measured voltage.

[0021] Optionally, a second type of load change event is detected if there is a measured voltage change corresponding to a change in the load on the circuit provided by one or more electrical loads in one of the multiple electrical loads in a branch circuit other than the monitored branch circuit, and a corresponding change exists in the measured current. In this example, for the second type of load change event, the corresponding change in the measured current does not correspond to a change in the load on the circuit provided by one or more electrical loads in the monitored branch circuit. The difference between the first type of load change event and the second type of load change event is that the measured current change corresponding to the first type of load change event is greater than the measured current change corresponding to the second type of load change event.

[0022] For example, for a type II load change event, the change in measured current (corresponding to a change in measured voltage) can be ignored. For instance, the change in the magnitude of the measured current between consecutive peaks or between consecutive peaks and troughs corresponding to a type II load change event can be a decrease or increase of less than 5% in the magnitude of the measured current. In other words, the change in measured current corresponding to a load change on a circuit supplied by one or more electrical loads in one of a plurality of electrical loads in a branch circuit other than the monitored branch circuit is much smaller than the change in measured current corresponding to a load change on a circuit supplied by one or more electrical loads in the monitored branch circuit.

[0023] Optionally, for each of the first and second types of load change events, the measured voltage change exceeds a voltage threshold change. For example, the voltage threshold change may be defined for the measured voltage change between consecutive peaks or between consecutive peaks and troughs in the measured voltage. Alternatively, or additionally, the voltage threshold change may be defined within a specified time period. The specified time period may correspond to the time it takes for the voltage in each branch of the circuit to stabilize after a load change on the circuit supplied by one or more electrical loads among a plurality of electrical loads.

[0024] For example, the voltage threshold change can be configured to exceed any change in the measured voltage originating from the power supply.

[0025] For example, each load change event of type I or type II can indicate that an appliance in the circuit is switching between an off state and an on state. A type I load change event can indicate that an appliance in the monitored branch circuit is switching between an off state and an on state, while a type II load change event can indicate that an appliance in one of the other branch circuits is switching between an off state and an on state.

[0026] In one example, the method includes: estimating the total current I in the circuit according to the following equation. 供应 :

[0027]

[0028] Among them I 供应 It is the total current in the circuit; V 供应 It is the voltage of the power supply; it is the measured voltage; and RL is an estimate of the line impedance; and the estimated total current I is used. 供应 This allows for the estimation of the total power consumption in the circuit. In this way, the total current in multiple branches can be estimated based on voltage measurements from a single branch, eliminating the need for current sensors in other branches.

[0029] Optionally, the total current I in the circuit can be estimated in response to (or dependent on) the detection of a first-type or second-type load change event. 供应 .

[0030] In one example, the method includes: detecting a series of load change events of type I and / or type II over a period of time based on corresponding changes in the measured voltage; and estimating the total current I in the circuit in a stepwise manner that varies over time. 供应 The continuous step changes ΔI supply of the total current in the circuit correspond to continuous load change events in a series of load change events, and each of the continuous step changes ΔI supply of the total current in the circuit is estimated according to the following equation:

[0031]

[0032] Where ΔIsupply is the step change in the total current in the circuit corresponding to one of a series of load change events; ΔV1 is the measured voltage change corresponding to that load change event; and RL is an estimate of the line impedance; and the estimated total current Isupply is used... 供应 This is used to estimate the total power consumption in the circuit. In this way, changes in total current and / or total power can be estimated by aggregating the changes caused by each load change event. In one example, ΔV1 can take the form of changes or step changes in the measured voltage between consecutive peaks or between consecutive peaks and troughs corresponding to the load change events in a series of load change events.

[0033] Optionally, the estimate of the total power usage of the circuit is based on an estimate of the total current and the measured voltage.

[0034] According to another aspect of this disclosure, a non-transitory computer-readable storage medium having instructions stored thereon that, when executed by a processor, cause the processor to perform the method described in another aspect of the invention.

[0035] According to another aspect of this disclosure, a control system for a power distribution device for multiple electrical loads is provided. The power distribution device includes a circuit comprising: a plurality of branch circuits arranged in parallel; a current sensor arranged for measuring the current in a monitored branch circuit among the plurality of branch circuits; and a voltage sensor arranged for measuring the voltage across one of the branch circuits. In use, each branch circuit is coupled to one or more of the plurality of electrical loads, and the power distribution device is configured to distribute power received from a power supply via a power supply line across the circuit. In use, the control system is configured to estimate the total power usage of the circuit according to the method described in the preceding aspect of the invention.

[0036] It should be understood that preferred and / or optional features of each aspect of this disclosure may also be incorporated, individually or in appropriate combinations, into other aspects of the invention. Attached Figure Description

[0037] Examples of this disclosure will now be described with reference to the accompanying drawings, in which:

[0038] Figure 1 A schematic diagram of a circuit formed by a power distribution device for distributing power supply to multiple electrical appliances in a building is shown.

[0039] Figure 2 It shows the method for determining Figure 1 The steps for using electricity at the power distribution unit;

[0040] Figure 3 It shows Figure 2 The sub-step of the first step of the method shown;

[0041] Figure 4 It shows Figure 1 The graph shows the magnitude of the current in the monitored branch circuit of the power distribution unit and the magnitude of the voltage across the monitored branch of the power distribution unit.

[0042] Figure 5 It shows Figure 2 The sub-step of the second step of the method shown;

[0043] Figure 6 It shows the corresponding Figure 4 The interpeak current signal of the current curve and the corresponding Figure 4 The interpeak voltage signal of the voltage curve in the image;

[0044] Figure 7 It shows Figure 4 The enlarged version of the exemplary curve showing the voltage magnitude across the monitored branch, as illustrated, indicates... Figure 6 The peaks and troughs identified in the inter-peak voltage signal shown;

[0045] Figure 8 An example is shown. Figure 1 An exemplary inter-peak voltage signal of one or more load change events in a circuit;

[0046] Figure 9 It shows the method for determining Figure 1 Load change events during the operation of one or more electrical appliances in a circuit. Figure 2 The third step of the method shown is a sub-step;

[0047] Figure 10 It shows in Figure 2 The method shown illustrates an exemplary simulation of the line impedance estimate obtained and the variation of the error of that estimate over time when another load change event is detected; and

[0048] Figure 11 It shows that according to Figure 2 The method shown obtains Figure 1 An exemplary curve of the total current in the branch circuit of the power distribution unit shown. Detailed Implementation

[0049] Embodiments of this disclosure relate to a method for determining the total electrical power used by electrical appliances in a building based on the current and voltage in a single branch circuit (i.e., the monitored branch circuit) of a power distribution unit that distributes power supply among the appliances. Such a method involves measuring the voltage in one branch circuit and using an estimate of the line impedance between the power distribution unit and the power source (e.g., a power distribution network) to estimate the total current flowing through each branch circuit. The total electrical power used by the appliances can then be determined based on the voltage measurement and the estimate of the total current.

[0050] Advantageously, determining the total current based on an estimate of the line impedance reduces the need to measure the current in each branch circuit of the power distribution unit. Therefore, even if the power distribution unit does not include operating current sensors in each branch circuit, the total power usage can be determined by the power distribution unit.

[0051] As will become clear in the following description, the exemplary method of the present invention also determines or improves the estimation of line impedance. In particular, when the electrical load in the monitored branch circuit changes, for example when an appliance in the monitored branch circuit is turned on / off, the line impedance can be estimated by measuring the current in the monitored branch circuit and the voltage across one of the multiple branch circuits.

[0052] This change is identifiable because when appliances are switched on or off, the voltage in each branch circuit of the power distribution unit will show sharp drops and rises over time, thus altering the total electrical load.

[0053] The voltage change caused by the impedance in the power supply line connecting the power source to the distribution unit effectively creates a voltage divider circuit that distributes the voltage of the power source between the distribution unit and the power supply line.

[0054] When the total load changes over time, and the line impedance remains relatively constant, the voltage measured in the branch circuits across the distribution unit will change proportionally to the change in the total electrical load. Therefore, the method of this invention uses this phenomenon to identify changes in the operating state of electrical appliances in the monitored branch circuits and improves the estimation of line impedance. Furthermore, the improved estimation of line impedance provides an improved estimate of the total current flowing into the building and the corresponding power usage.

[0055] It is anticipated that this invention will be able to reduce instrumentation costs for low-voltage electrical systems in buildings or other locations. This advantage stems from the ability to determine the total current flowing into a building, and the corresponding power consumption of the building's appliances based on current measurements from individual branch circuits.

[0056] Figure 1 An exemplary circuit 1 for supplying power to multiple electrical appliances in a building is schematically shown. Circuit 1 is characterized by a power source 2, a power distribution unit 4, and a power supply line 6.

[0057] Power source 2 provides a power supply intended to power the operation of electrical appliances in the building. In this example, power source 2 is supplied by a distribution network. More specifically, power source 2 may correspond to the power output of a transformer from the distribution network closest to the building. Therefore, in this example, power source 2 supplies circuit 1 with power including alternating current and alternating voltage. It should be understood that in other examples, the power source may take other forms.

[0058] For the purposes of the following description, it is assumed that the alternating current supplied by power source 2 has a constant amplitude and frequency. However, those skilled in the art will understand that the alternating power supplied by the distribution network is subject to time-varying fluctuations originating from the distribution network. Such fluctuations can, for example, cause the magnitude of the alternating current to increase and / or decrease by less than 5%. In particular, fluctuations can cause the magnitude of the alternating current to increase and / or decrease by less than 2%. In this document, such a variation of the power supply is referred to as power fluctuation.

[0059] exist Figure 1 In the diagram, power supply line 6 is schematically shown as a pair of lines 6a and 6b extending between corresponding connection points to power source 2 and distribution unit 4. In this way, power supply line 6 electrically connects power source 2 to distribution unit 4, and conducts power through power supply line 6 to distribution unit 4 to supply power to the building's electrical appliances.

[0060] For example, power line 6 can take the form of a service entry point, connecting the incoming line from the distribution network or transformer to the distribution unit 4. Figure 1 In the diagram, the line impedance of the power supply line 6 is schematically represented by the resistor 8 arranged on the power supply line 6 and between the power source 2 and the distribution device 4.

[0061] In this example, the power distribution device 4 takes the form of a switchboard, but it should be understood that in other examples, the power distribution device may take other forms suitable for the building's power distribution requirements, such as a switchboard, circuit breaker panel, or electrical panel.

[0062] The power distribution unit 4 includes multiple branch circuits 10a-c connected to electrical appliances in the building and a control system 12 configured to determine the power usage of the multiple branch circuits 10a-c. The multiple branch circuits 10a-c are arranged in parallel, wherein each branch circuit 10a-c begins and terminates at the connection point of the power distribution unit 4 to the power supply line 6.

[0063] In this example, the multiple branch circuits 10a-c include a first branch circuit 10a, a second branch circuit 10b, and a third branch circuit 10c. For simplicity, each of the multiple branch circuits 10a-c is connected to an electrical appliance in the building, and the electrical load corresponding to the operation of each appliance is... Figure 1 The circuit is schematically represented by corresponding resistors 11a-c arranged in each branch circuit 10a-c. Each branch circuit 10a-c also includes a corresponding switch (not shown) for selectively changing the state of the corresponding electrical appliance between an on state and an off state.

[0064] To provide some context for the following description, in this example, the electrical load 11a corresponding to the appliance in the first branch circuit 10a has a resistance of 15 ohms and draws power when the appliance is on, but does not draw power when the appliance is off. Similarly, the electrical load 11b corresponding to the appliance in the second branch circuit 10b has a resistance of 20 ohms and draws power when the appliance in the second branch circuit 10b is on, but does not draw power when the appliance is off. The electrical load 11c corresponding to the appliance in the third branch circuit 10c has a resistance of 25 ohms and draws power when the appliance in the third branch circuit 10c is on, but does not draw power when the appliance is off.

[0065] It should be understood that in other examples, the multiple branch circuits may include any number of branch circuits, and each of the multiple branch circuits may be connected to one or more electrical appliances, each of which forms a corresponding electrical load in the branch circuit or together forms a total electrical load in the branch circuit.

[0066] The power distribution unit 4 includes at least one voltage sensor configured to measure the voltage across one of the plurality of branch circuits 10a-c and output a signal to the control system 12 indicating the measured voltage. As previously mentioned, the voltages across the branch circuits are equal; therefore, in this example, the power distribution unit 4 includes a single voltage sensor 16 configured to measure the voltage across the third branch circuit 10c. Figure 1 As shown. It should be understood that, due to the parallel arrangement, the voltage measured across the third branch 10c will be equal to the voltage across the first branch 10a and the voltage across the second branch 10b.

[0067] like Figure 1 As shown, in this example, the first branch circuit 10a is a 'monitored branch circuit' that includes a current sensor 14 configured to measure the current flowing through it and output a signal indicating the measured current to the control system 12. In other words, the first branch circuit 10a is designated as a 'monitored branch circuit' because it includes a current sensor 14 configured to measure the current in the first branch circuit 10a and transmit the measured current to the control system 12. It should be noted that in this example, only one of the multiple branch circuits 10a-c includes the operating current sensor 14.

[0068] Generally, during the connection of the power distribution unit 4 to the electrical appliances of the building, the monitored branch circuit 10a, i.e., the branch circuit in which the current sensor 14 is connected, is selected from multiple branch circuits 10a-c. Selection, i.e., choosing which branch circuit is connected to the current sensor 14, is important. Specifically, the monitored branch circuit 10a can be selected from multiple branch circuits 10a-c based on the fact that the electrical appliances or loads in the branch circuit may be individually turned on / off, i.e., no other electrical appliances / loads are individually turned on / off in other branches during the same time period.

[0069] Therefore, a monitored branch circuit can be selected from multiple branch circuits 10a-c based on one or more of the following factors: the number of electrical appliances in each branch circuit (which can be minimized in the monitored branch circuit); the size of the electrical load in each branch circuit (which can be maximized in the monitored branch circuit); and the frequency at which the electrical appliances in each branch circuit change state (which can be configured to maximize the probability that the electrical appliances in the monitored branch circuit will change between the on and off states, while the electrical appliances in other branch circuits are in the off state).

[0070] In other examples, the power distribution unit may include a current sensor in each branch circuit, as in a conventional distribution board. In this case, for example under certain conditions, the monitored branch circuit can be manually selected from multiple branch circuits, or the power distribution unit can be configured to electronically select the monitored branch circuit from multiple branch circuits. For example, if the current sensor in one of the multiple branch circuits fails, making it impossible to determine the power usage in each branch circuit, the control system of the power distribution unit may be configured to designate one of the branch circuits as the monitored branch circuit. For example, the control system may select the monitored branch circuit based on any of the factors described above. The designated branch circuit will include an operating current sensor, and the control system can continue to determine the total power usage of the multiple branch circuits according to the method of the present invention described herein.

[0071] In this way, it should be understood that the exemplary method of the present invention can be applied to Figure 1 The power distribution device 4 shown is applicable to the conventional power distribution device described above, which includes a current sensor in each branch circuit.

[0072] The control system 12 may include one or more controllers configured to receive signals from current sensor 14 indicating the current in the first branch circuit 10a; receive signals from voltage sensor 16 indicating the voltage across one of the plurality of branch circuits 10a-c; and determine, according to the method of the invention: the total current in the plurality of branch circuits; an estimate of the line impedance between the power source 2 and the plurality of branch circuits 10a-c; and / or the total power consumption of the plurality of branch circuits 10a-c; based on the first and second signals. The control system 12 may also be configured to output the total power consumption of the plurality of branch circuits 10a-c to implement a more complex energy allocation strategy.

[0073] For the purposes of this disclosure, it should be understood that the controllers described herein may each include a control unit or computing device having one or more electronic processors. A set of instructions may be provided that, when executed, cause the controller or control unit to perform the control techniques (including the methods described herein). This set of instructions may be embedded in one or more electronic processors, or alternatively, may be provided as software to be executed by one or more electronic processors. The set of instructions may be embedded in a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium), which may include any mechanism for storing information in a form readable by a machine or electronic processor / computing device, including but not limited to: magnetic storage media (e.g., floppy disks); optical storage media (e.g., CD-ROMs); magneto-optical storage media; read-only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROMs and EEPROMs); flash memory; or electrical or other types of media for storing such information / instructions.

[0074] Now refer to Figure 2 An exemplary method 20 for determining the power usage of multiple branch circuits 10a-c is described. The figure schematically illustrates method 20, and further reference is made to the description supporting method 20. Figures 3 to 1 3.

[0075] It should be understood that method 20 includes multiple steps for determining the total power usage of the multiple branch circuits 10a-c, which varies over time, and although method 20 has a generally sequential manner, it should be understood that one or more of the multiple steps may be performed more than once and / or simultaneously with other steps of method 20.

[0076] In step 22, method 20 includes determining the current in the monitored branch circuit 10a and determining the voltage across one of the branch circuits 10a-c.

[0077] In this example, current sensor 14 is used to measure the current in the monitored branch circuit 10a, and voltage sensor 16 measures the voltage across the third branch circuit 10c. Each of the current and voltage measurements can be sampled at a sufficient rate to accurately capture the waveform of the power supply. For example, for a power supply from a UK distribution network, each of the current and voltage measurements could be sampled at a rate of 4 kHz.

[0078] Voltage and current measurements are stored in buffers, allowing a series of buffered voltage measurements to form a voltage waveform, and a series of buffered current measurements to form a current waveform. For example, each sampled current measurement may be output from current sensor 14 to control system 12, and each sampled voltage measurement may be output from voltage sensor 16 to control system 12. Control system 12 may store each current and each voltage measurement, along with a corresponding timestamp that can be used to form the voltage and / or current waveforms, in a memory device (not shown) of control system 12.

[0079] This process is in Figure 3 The diagram schematically illustrates the following: acquiring a voltage measurement in step 22a; attaching the voltage measurement to a buffer in step 22b; and in step 22c, deciding whether to proceed to step 24 if at least two voltage measurements are stored in the buffer. Figure 3 It is also shown that: in step 22d, a current measurement is acquired; in step 22e, the current measurement is attached to the buffer; and in step 22f, if at least two current measurements are stored in the buffer, a decision is made on whether to proceed to step 24.

[0080] Figure 4 An exemplary current waveform 40 is shown, generated by plotting the absolute value of a current measurement stored in a buffer, and an exemplary voltage waveform 42 is shown, generated by plotting the absolute value of a voltage measurement stored in a buffer during the same time period as the current measurement.

[0081] As shown in the figure, the exemplary current waveform 40 illustrates the period of 0 amperes when the appliance in the first branch circuit 10a is turned off, and the period of non-zero current when the appliance in the first branch circuit 10a is turned on. The graph defined by the voltage waveform 42 will become clear in the following description.

[0082] Once multiple current measurements and multiple voltage measurements have been determined and stored in a buffer, forming current and voltage waveforms, method 20 can proceed to step 24.

[0083] It should be understood that as method 20 proceeds through subsequent steps, additional measurements can be added to the corresponding waveform.

[0084] In step 24, method 20 includes determining the peaks and troughs of a voltage waveform based on buffered voltage measurements, and determining the peaks and troughs of a current waveform based on buffered current measurements.

[0085] Those skilled in the art will understand that the peaks and troughs of voltage and current waveforms can be determined using various analytical methods. Therefore, the following examples are not intended to limit the scope of the invention.

[0086] For each waveform, peaks and troughs can be detected, for example, by determining the forward difference between successive measurements. For instance, a peak can be identified if the forward difference between the first and second successive measurements is greater than zero (indicating a positive slope or an upward slope) and the forward difference between the second and third successive measurements is less than or equal to zero (indicating a flat slope or a decreasing slope).

[0087] When using the absolute or root mean square (RMS) values ​​of current / voltage measurements, troughs can be detected in the same way as peaks. Alternatively, for example, a trough can be detected if the forward difference between the first and second consecutive measurements is less than zero, and the forward difference between the second and third consecutive measurements is equal to or greater than zero.

[0088] It should be understood that the peaks and troughs in the voltage waveform should substantially correspond to the peaks and troughs in the current waveform, except for the period during which the electrical load in the monitored branch circuit 10a is zero (because the current also drops to zero).

[0089] In some examples, to limit the search and reduce the computational complexity of determining peaks and troughs, if the current is greater than a peak current threshold, only continuous current measurements can be compared to identify peaks / troughs. Similarly, if the voltage is greater than a peak voltage threshold, only continuous voltage measurements can be compared to identify peaks / troughs. In such examples, setting appropriate peak current and voltage thresholds can rely on knowledge of the voltage and / or current amplitudes of the power supply from source 2. For example, if the power supply is 240 volts, the peak voltage threshold could be 200 volts.

[0090] For clarity, in Figure 5The diagram schematically illustrates the step-by-step process for determining the peak of a voltage waveform. In step 24a, a first voltage measurement and a second consecutive voltage measurement are compared with a peak voltage threshold. If the first and second voltage measurements exceed the peak voltage threshold, the forward difference between the first and second measurements is determined in step 24b and stored in a buffer in step 24c. Steps 24a and 24b are then repeated for the second and third consecutive voltage measurements. In step 24d, it is determined whether the forward difference (stored in the buffer) between the first and second voltage measurements is greater than or equal to zero, and in step 24e, it is determined whether the forward difference between the second and third voltage measurements is less than or equal to zero. If steps 24d and 24e are satisfied, a peak is detected in step 24f.

[0091] In other examples, as those skilled in the art will understand, backward differential or other methods for determining the peaks and troughs of current and / or voltage waveforms may be used.

[0092] In any case, when arranged in series, the detected peaks and troughs of the voltage waveform form an inter-peak voltage signal, and the detected peaks and troughs of the current waveform form an inter-peak current signal. An exemplary inter-peak current signal 50 using the absolute value of a current measurement, together with an exemplary inter-peak voltage signal 52 using the absolute value of a voltage measurement, is used in… Figure 6 As shown in the figure, the time periods of the inter-peak current signal 50 and the inter-peak voltage signal 52 are the same.

[0093] To enhance the details, Figure 7 It shows Figure 4 The enlarged version of voltage waveform 42 shown indicates the identified peaks and troughs.

[0094] As will become clear in the following description, the power consumption of the appliances varies with the total electrical load, and the electrical load in each branch circuit 10a-c varies according to the operating state of the appliances in that branch circuit. For example, when one of the appliances in branch circuit 10a-c is turned on or off, the electrical load in the corresponding branch circuit 10a-c increases or decreases accordingly. Therefore, it is useful to detect changes in the operating state of the appliances for the purpose of determining the total power consumption. In the following description, each change in the operating state of the appliances in one of the multiple branch circuits 10a-c is referred to as a 'load change event'.

[0095] Furthermore, for the purpose of estimating the line impedance in power supply line 6, it is particularly useful to identify specific types of load change events corresponding to changes in the electrical load in the monitored branch circuit 10a. In the following description, each change in the operating state of the electrical appliances in the monitored branch circuit 10a is referred to as a 'Monitored Load Change Event (MLCE)'.

[0096] Therefore, in step 26, method 20 includes detecting one or more load change events of the first type, wherein the operating state of an appliance in one of the plurality of branch circuits 10a-c changes, and detecting one or more load change events of the second type, namely MLCE.

[0097] When the electrical load of any branch circuit 10a-c increases, the measured voltage decreases sharply and correspondingly. Conversely, whenever the electrical load of any branch circuit 10a-c decreases, the measured voltage increases sharply.

[0098] If the electrical load of any branch circuit 10a-c increases, the measured current will also increase suddenly, and if the electrical load of any branch circuit 10a-c decreases, the measured current will decrease suddenly.

[0099] In this way, each load change event is characterized by a rapid change in current / voltage, which is different in nature from the random current changes caused by the power fluctuations described earlier.

[0100] Furthermore, the current in each branch circuit 10a-c depends on the corresponding electrical load of that branch circuit 10a-c. Therefore, if the electrical load of the monitored branch circuit 10a increases, the measured current will increase by a greater amount compared to the measured current change corresponding to an increase in the electrical load in one of the other branch circuits 10b-c. Similarly, if the electrical load of the monitored branch circuit 10a decreases, the measured current will decrease by a greater amount compared to a corresponding decrease in the electrical load in one of the other branch circuits 10b-c.

[0101] Therefore, a load change event caused by a change in the electrical load of the monitored branch circuit 10a, i.e., MLCE, can be distinguished from a load change event caused by a change in the electrical load of one of the other branch circuits 10b-c.

[0102] Therefore, in step 26, method 20 can detect one or more load change events and / or MLCES by analyzing the changes in the measured current and the measured voltage.

[0103] It should be understood that changes in voltage and / or current measurements corresponding to the switching on / off of electrical appliances can be determined using various analytical methods. Therefore, the following examples are provided for clarity and are not intended to be limiting.

[0104] In one example, in step 26, load change events, including MLCE, are detected by determining the forward or backward difference between consecutive peaks and troughs in the inter-peak voltage signal 52 and / or the inter-peak current signal 50. Any changes in the inter-peak signals are compared to corresponding thresholds, which can be configured to represent load change events, such as MLCE, rather than random fluctuations in the power supply from power source 2.

[0105] For example, a load change event can be detected if there is a sharp or gradual voltage change between the peaks and troughs that exceeds a corresponding voltage difference threshold. Alternatively, a load change event can be detected if there is a sharp or gradual current change between the peaks and troughs that exceeds a corresponding current difference threshold.

[0106] The voltage difference threshold and current difference threshold should each be large enough to filter out power fluctuations, i.e., parasitic changes in voltage / current caused by distribution network noise. For example, the voltage difference threshold may be less than or equal to 5% of the amplitude of the maximum voltage in the inter-peak voltage signal 52 or the voltage from source 2. Similarly, the current difference threshold may be less than or equal to 5% of the amplitude of the maximum current in the inter-peak current signal 50 or the current from source 2.

[0107] Generally, load change events can be indicated by changes in measured current and / or measured voltage. However, for easy detection of MLCEs, a current difference threshold can be configured to filter out load change events caused by changes in the state of appliances in unmonitored branch circuits 10b-c, i.e., branch circuits 10b-c other than the monitored branch circuit 10a. This is possible because the current change caused by a load change event in the monitored branch circuit 10a is much larger than the current change caused by a load change event in the other branch circuit 10b-c. This current difference threshold can be determined empirically, for example.

[0108] In this way, the voltage difference threshold can be configured to identify load change events in any branch circuit, while the current difference threshold can be configured to identify load change events only in the monitored branch circuit 10a.

[0109] Therefore, in step 26, method 20 can determine the load change event and MLCE based on the inter-peak voltage signal 52 and inter-peak current signal 50 as described below.

[0110] If the peak-to-peak voltage signal 52 decreases between peaks and consecutive troughs and the difference between peaks and troughs is greater than a threshold voltage difference, it indicates that an appliance is switched on in one of the multiple branch circuits 10a-c). In this case, a load change event referred to as a 'voltage switching event' can be marked.

[0111] If the peak-to-peak voltage signal 52 increases between peaks and consecutive troughs and the difference between peaks and troughs is greater than a threshold voltage difference, it indicates that an appliance has been turned off in any of the multiple branch circuits 10a-c). In this case, a load change event referred to as a 'voltage shutdown event' can be marked.

[0112] As an example, Figure 8 An exemplary inter-peak voltage signal 52 is shown, wherein a voltage turn-on event 54 is marked after the inter-peak voltage signal 52 decreases sharply, and a subsequent voltage turn-off event 56 is marked after the inter-peak voltage signal 52 increases sharply.

[0113] If the peak-to-peak current signal 50 increases between peaks and consecutive troughs and the difference between peaks and troughs is greater than a threshold current difference, it indicates that the electrical appliance in the monitored branch circuit 10a is switched on. In this case, a load change event referred to as a 'current switching event' can be marked.

[0114] If the peak-to-peak current signal 50 decreases between peaks and consecutive troughs and the difference between peaks and troughs is greater than a threshold current difference, it indicates that the electrical appliance in the monitored branch circuit 10a has been turned off. In this case, a load change event referred to as a 'current shutdown event' can be marked.

[0115] For clarity, Figure 9 The diagram schematically illustrates the step-by-step process for determining a load change event, showing that: in step 26a, the forward difference between the absolute values ​​of the peaks and consecutive troughs of the peak-to-peak voltage signal 52 is determined, and in step 26b, it is determined whether the forward difference is greater than a threshold voltage difference. If the forward voltage difference is greater than the threshold voltage difference, a voltage shutdown event is marked in step 26c. If the forward voltage difference is less than the threshold voltage difference, it is determined in step 26d whether the forward voltage difference is less than a negative threshold voltage difference. If the forward voltage difference is less than the negative threshold voltage difference, a voltage shutdown event is marked in step 26e.

[0116] Figure 9The diagram also illustrates determining the forward difference between the absolute values ​​of the peaks and consecutive troughs of the inter-peak current signal 50 in step 26f, and determining in step 26g whether this forward difference is greater than a threshold current difference. If the forward difference is greater than the threshold current difference, a current-on event is marked in step 26h. If the forward difference is less than the threshold current difference, it is determined in step 26i whether the forward difference is less than a negative threshold current difference. If the forward difference is less than the negative threshold current difference, a current-on event is marked in step 26j.

[0117] In some examples, each load change event can also be verified by monitoring whether the voltage and / or current stabilizes after the detected load change event. For example, stability can be determined by comparing the last peak / trough of the current / voltage with one or more subsequent peaks / troughs of the current / voltage to determine whether the change is transient and possibly caused by noise, or more persistent and more likely to correspond to an appliance switching event. For example, a transient change may last less than 5 seconds. Similarly, a steady-state algorithm incorporating a steady-state delay can be used, which forces the algorithm to record the current and voltage changes for a short period of time, such as 5 seconds, after detecting the initial load change event, such that the voltage / current change corresponds to the steady state of the changing electrical load.

[0118] As time progresses, each of these load change events will be detected in step 26 when the building's electrical appliances are switched on or off.

[0119] It should be understood that simultaneous voltage-on and current-on events, or simultaneous voltage-off and current-off events, will indicate a load change event in the monitored branch circuit 10a, i.e., MLCE. Conversely, a voltage-on event or voltage-off event without a corresponding current-on or current-off event will indicate a load change event in one of the other branch circuits 10b-c.

[0120] For each MLCE, the absolute value of the peak-to-peak voltage signal 52 can also be stored in a buffer for subsequent determination of the line impedance estimate. For example, the absolute value of the peak-to-peak voltage signal 52 at the beginning of each MLCE can be stored in the memory storage device of the control system 12. These absolute values ​​are referred to as the voltage of the corresponding MLCE in the following description, and the use of these values ​​will become clear in a later part of this description.

[0121] As will become clear in the following description, when MLCE occurs alone, i.e., when the electrical load in other branch circuits is substantially constant, the resulting change in the measured voltage is inversely proportional to the change in the measured current. Furthermore, the proportionality constant between the change in the measured voltage and the change in the measured current corresponds to the line impedance in power supply line 6, i.e., the line impedance between power supply 2 and the multiple branch circuits 10a-c.

[0122] Therefore, in step 28, method 20 includes determining an estimate of the line impedance based on the changes in current and voltage measured in the monitored branch circuit 10a due to the MLCE detected in step 26. The process and the principles employed will be explained in more detail in the following description.

[0123] It should be understood that the first branch circuit, the second branch circuit, and the third branch circuit 10a-c of the power distribution device 4 have currents I1, I2, and I3, and voltages V1, V2, and V3, respectively. The voltage V3 across the third branch circuit 10c is measured by the voltage sensor 16, and due to the parallel arrangement, the voltages V1, V2, and V3 across each branch circuit 10a-c are equal to each other.

[0124] The current I1 in the first branch circuit 10a is measured by the current sensor 14, but the currents I1, I2, and I3 in each branch circuit 10a-c are not equal. Instead, the currents I1, I2, and I3 conducted through the branch circuits 10a-c are added together to give the total current I. 供应 .

[0125] The total current I in the multiple branch circuits 10a-c 供应 This is equal to the current conducted along power supply line 6, and as previously stated, the impedance in power supply line 6 effectively creates a voltage divider circuit that divides the voltage of power supply 2 between the multiple branch circuits 10a-c and power supply line 6 itself. The line impedance is relatively fixed and can be considered constant.

[0126] Therefore, the total current I 供应 It can be determined based on the following equation:

[0127]

[0128] Where t reflects the total current I 供应 The time-varying nature of V; V supply is the voltage of the power supplied by power source 2; V1(t) is the time-varying voltage across the monitored branch circuit 10a, which is equal to the time-varying voltage V3(t) measured by voltage sensor 16; and RL is the line impedance of power supply line 6.

[0129] For simplicity, inductive loads are not considered in this example, and it is assumed that circuit 1 is purely resistive, i.e., there is no reactive power. This approach is easy to generalize.

[0130] If the electrical load in one of the multiple branch circuits 10a-c changes, for example due to an appliance being switched on or off (i.e., due to a load change event), the total current I... 供应 There will be corresponding changes. In other words, the total current I 供应 It varies according to each load change event identified in step 26. (By ΔI) 供应 The total current I represents 供应 The final change of (t) can be determined by the following equation:

[0131]

[0132]

[0133] Where ΔV1 is the voltage change across one of the multiple branch circuits 10a-c corresponding to a load change event. Therefore, the line impedance RL can be determined based on ΔI. 供应 It is determined by ΔV1.

[0134] Furthermore, if the change in total current ΔI 供应 The change in total current ΔI is due to the change in the electrical load of the monitored branch circuit 10a, and especially due to the isolated MLCE. 供应 This can be considered equal to the change in current ΔI1 in the monitored branch circuit 10a. This gives the following equation:

[0135]

[0136] In this way, the line impedance can be estimated based on the voltage and current changes in the monitored branch circuit 10a caused by MLCE.

[0137] Therefore, in one example, step 28 involves determining an estimate of the line impedance RL according to Equation 4, where ΔV1 is the step change (or voltage difference) in the inter-peak voltage signal 52 of the MLCE detected in step 26, and ΔI1 is the step change (or current difference) in the inter-peak current signal 50 of the MLCE.

[0138] It should be understood that estimating the line impedance RL according to Equation 4 relies on the assumption that the electrical load (and therefore the current) in the unmonitored branch circuits 10b-c is constant during MLCE. In reality, such a condition may be relatively uncommon in a given building, and the electrical load (and therefore the current) in the unmonitored branch circuits 10b-c is unlikely to remain constant during a randomly selected MLCE.

[0139] Therefore, in step 28, some examples of the invention include additional measurements to maximize the accuracy of the estimated line impedance RL based on available data.

[0140] Specifically, according to Equation 4, the estimate of the line impedance RL is most accurate when the electrical load of the monitored branch circuit 10a is the most significant. For example, this might be the case when appliances in other branch circuits 10b-c are turned off, resulting in minimal electrical load.

[0141] Furthermore, the absence of electrical load in other branch circuits 10b-c can be inferred from voltage measurements. For example, the measured voltage is maximized when the total electrical load is minimized.

[0142] Therefore, in some examples, whenever an MLCE is detected in step 26, method 20 can determine an estimate of the line impedance RL in two stages. In the first stage, the voltage of the newly detected MLCE can be compared with the estimated line impedance RL based on the voltage of the MLCE.

[0143] In the second stage, if the voltage of the newly detected MLCE is greater than the voltage of the previously estimated MLCE used to determine the line impedance RL, the estimate of the line impedance RL can be recalculated based on the newly detected MLCE according to Equation 4.

[0144] When comparing the voltage of a newly detected MLCE with the voltage of a previously used MLCE to determine the estimated line impedance RL, it may be preferable to compare the corresponding voltage of the inter-peak voltage signal 52 at the beginning (or immediately before) each MLCE for consistency.

[0145] Furthermore, when recalculating the estimate of the line impedance RL based on the newly detected MLCE, it should be understood that ΔV1 in Equation 4 corresponds to the step change (or voltage difference) in the inter-peak voltage signal 52 of the newly detected MLCE. Similarly, ΔI1 in Equation 4 corresponds to the step change (or current difference) in the inter-peak current signal 50 of the newly detected MLCE.

[0146] As time progresses, an increasing number of MLCEs will be detected when appliances in the monitored branch circuit 10a are switched on and off, and it is assumed that the electrical load on the monitored branch circuit 10a will eventually be activated individually (with the maximum measured voltage). The MLCEs corresponding to this action will be detected in step 26 and used in step 28 to determine an estimate of the line impedance RL, such that the error in the estimate of the line impedance RL will eventually be reduced to zero.

[0147] As an example, Figure 10An exemplary curve showing how the error 58 in the estimation of the line impedance RL changes over time is shown. As illustrated, when the MLCE occurs at a higher voltage, i.e. with a smaller total electrical load, the error 58 decreases in a step-like manner. Eventually, after the MLCE occurs in isolation, the error 58 decreases to zero or a negligible amount.

[0148] In step 30, method 20 includes determining the total current I in the multiple branch circuits 10a-c using an estimate of the line impedance RL and the voltage across one of the multiple branch circuits 10a-c (e.g., measured by voltage sensor 16). 供应 .

[0149] Those skilled in the art will understand that once the estimate of the line impedance RL is determined in step 28, there exists a method for determining the total current I in the multiple branch circuits 10a-c. 供应 Various methods are available. Therefore, the following examples are not intended to limit the scope of the invention.

[0150] In one example, the total current I 供应 It can be determined in step 30 according to Equation 1, where V_supply is the voltage amplitude of the power supplied by power source 2; V1(t) is defined by the inter-peak voltage signal 52 determined in step 24; and RL is the line impedance of power supply line 6.

[0151] In another example, we can assume the total current I 供应 The load change events detected in step 26 are constant. In this case, the total current I... 供应 It can be determined in step 30 according to Equation 1, where Vsupply is the voltage amplitude of the power supplied by power source 2; V1(t) is a series of voltages corresponding to the voltages measured after each load change event detected in step 26; and RL is the line impedance of power supply line 6.

[0152] In this example, the total current I 供应 Forming a total current signal 60 in a step-by-step or digital manner, such as Figure 11 As shown in the example. In Figure 11 In the diagram, the current signal 60 is shown together with the actual total current 62 and the estimated error 64.

[0153] It should be understood that the total current I 供应 An equivalent approach can be taken by determining the total current change ΔI for each load change event detected in step 26. 供应 Then, in step 30, the total current change ΔI is accumulated. 供应 The change over time is used to determine the total current I. 供应 To determine.

[0154] In this case, for each load change event detected in step 26, the change in total current ΔI 供应 This can be determined according to Equation 2, where ΔV1 is the change in the peak-to-peak voltage signal 52 corresponding to the corresponding load change event. Next, by assuming the total current I... 供应 If the load remains constant between load change events, the total current I can be determined according to Equation 1. 供应 .

[0155] It should be understood that the total power consumption P in the multiple branch circuits 10a-c is equal to the voltage across one of the multiple branch circuits 10a-c multiplied by the total current I. 供应 As stated in the following equation:

[0156] (5)P=V1.I1+V2.I2+V3.I3=V1.(I1+I2+I3)=V1.I 供应

[0157] Therefore, in step 32, method 20 determines the total power consumption P at the multiple branch circuits 10a-c according to equation 5. In this way, based on the total current I determined in step 30... 供应 The total power is estimated using P, which is the voltage measured across one of the multiple branch circuits 10a-c (such as that provided by voltage sensor 16).

[0158] Those skilled in the art will understand that the total current I determined in step 30 供应 Various forms can be taken, as described above. Therefore, the estimate of electricity usage P can be similarly based on the total current I determined in step 30. 供应 Different forms may be adopted depending on the form. Therefore, the following examples are not intended to limit the scope of the invention.

[0159] In one example, the total current I determined in step 30 供应 It is assumed to be constant between load change events and determined in the manner described above. In this case, the total power usage of the multiple branch circuits 10a-c can be determined according to Equation 5, where the total current I... 供应 This is the time-varying stepwise signal determined in step 30, and V1 is the corresponding time-varying stepwise signal, which is formed by a series of voltages corresponding to the voltages measured after each load change event detected in step 26. In this way, the voltage V1 and the total current I can be compared. 供应 Multiply them to determine the total power usage. Alternatively, the voltage V1 and total current I at the end of each load change event can be multiplied. 供应 Multiply to determine the total power usage between load change events.

[0160] It should be noted that the steps of method 20 are provided only as examples of the present invention, and it should be understood that, as those skilled in the art will understand, steps can be changed, added, and removed.

[0161] For example, method 20 as described above includes steps for determining and refining an estimate of the line impedance RL, wherein an accurate estimate of the line impedance has not been previously determined. However, it should be understood that in other examples, once the estimate of the line impedance is determined, the total power usage of the multiple branch circuits 10a-c can be determined according to steps 30 and 32 of method 20.

[0162] Many modifications may be made to the above examples without departing from the scope of the appended claims.

Claims

1. A method for estimating power usage in a power distribution unit comprising multiple electrical loads, the power distribution unit including a circuit comprising a plurality of branch circuits arranged in parallel, each branch circuit coupled to one or more of the plurality of electrical loads, the power distribution unit being configured to distribute power received from a power supply via a power supply line across the circuit, the method comprising: Measure the voltage across at least one of the plurality of branch circuits; Measure the current in the monitored branch circuit among the plurality of branch circuits; as well as If there is a change in the measured current and a corresponding change in the measured voltage, a first type of load change event is detected, wherein the change in the measured current and the corresponding change in the measured voltage correspond to a change in the load on the circuit provided by the one or more electrical loads in the monitored branch circuit. The line impedance in the power supply line is estimated based on the detection of the first type of load change event. The estimation of the line impedance is based on the measured changes in current and voltage corresponding to the detected load change event of the first type. as well as The total power consumption of the circuit is estimated based on the following: the voltage of the power supply; the measured voltage; and the estimated line impedance; and The estimate of the line impedance RL is determined according to the following equation: Where RL is the estimated line impedance; ΔV1 is the measured voltage change corresponding to the detected first type of load change event; and ΔI1 is the measured current change corresponding to the detected first type of load change event. as well as The method further includes: estimating the total current I in the circuit according to the following equation. 供应 : Where I 供应 It is the total current in the circuit; V 供应 V1 is the voltage of the power supply; V1 is the measured voltage; and RL is the estimate of the line impedance; and Using the estimated total current I 供应 To estimate the total power consumption in the circuit.

2. The method according to claim 1, wherein, For the first type of load change event, the measured change in current exceeds a threshold change in current.

3. The method of claim 2, wherein the threshold change of the current is configured to exceed: Any variation in the measured current originating from the power supply; and Any change in the measured current corresponding to a change in the load on the circuit provided by one or more electrical loads in any of the branch circuits other than the monitored branch circuit.

4. The method according to any of the preceding claims, comprising: The line impedance should be re-estimated if the following conditions are met: Additional load change events of the first type were detected; and The measured voltage associated with the additional load change event of the first type is greater than the measured voltage associated with the load change event on which the current estimate of the line impedance is based; The re-estimation of the line impedance is based on the measured changes in current and voltage corresponding to the additional load change event of the first type.

5. The method according to claim 1, comprising: If there is a measured voltage change corresponding to a change in the load on the circuit provided by one or more of the plurality of electrical loads, a second type of load change event is detected.

6. The method according to claim 5, wherein, For each of the first and second types of load change events, the measured voltage change exceeds a voltage threshold change.

7. The method of claim 6, wherein the threshold change of the voltage is configured to exceed any change in the measured voltage originating from the power supply.

8. The method according to claim 1, comprising: If a measured voltage change exists corresponding to a change in load on the circuit provided by one or more of the plurality of electrical loads, a second type of load change event is detected, wherein the total current I in the circuit is estimated in response to detecting either the first type or the second type of load change event. 供应 .

9. The method according to any one of claims 5 to 7, comprising: Based on the corresponding changes in the measured voltage, a series of load change events of the first type and / or the second type are detected over a period of time; as well as The total current I in the circuit is estimated in a stepwise manner that varies over time. 供应 The continuous step changes ΔI supply of the total current in the circuit correspond to the continuous load change events in the series of load change events, and each of the continuous step changes ΔI supply of the total current in the circuit is estimated according to the following equation: Wherein ΔI supply is the step change in the total current in the circuit corresponding to one of the series of load change events; ΔV1 is the measured voltage change corresponding to the load change event; and RL is the estimate of the line impedance; as well as Using the estimated total current I 供应 To estimate the total power consumption in the circuit.

10. The method according to claim 8, wherein, The estimate of the total power used in the circuit is based on the estimate of the total current and the measured voltage.

11. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform the method according to any of the preceding claims.

12. A control system for a power distribution device for multiple electrical loads, the power distribution device comprising a circuit, the circuit comprising: The system comprises a plurality of branch circuits arranged in parallel, a current sensor arranged to measure the current in a monitored branch circuit among the plurality of branch circuits, and a voltage sensor arranged to measure the voltage across one of the branch circuits, wherein, in use, each branch circuit is coupled to one or more of the plurality of electrical loads, and the power distribution device is configured to distribute power received from a power supply via a power supply line across the circuit, and wherein, in use, the control system is configured to estimate the total power usage of the circuit using the method according to any one of claims 1 to 10.

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