A method and device for regulating three-phase imbalance in low-voltage power supply line

Abstract

The present invention discloses a method and device for regulating three-phase imbalance in a low-voltage power supply line, belonging to the technical field of three-phase imbalance regulation. The method comprises the following steps: in response to detecting the existence of three-phase imbalance in the low-voltage power supply line, obtaining the power consumption data of each user in the low-voltage power supply line; calculating the best path for adjusting the power consumption phase of the user according to the power consumption data of each user; and regulating the power consumption phase of the user who needs to be adjusted in the low-voltage power supply line according to the best path; the present invention improves the regulation efficiency of the three-phase imbalance by finding the best path for adjusting the power consumption phase of the user according to the power consumption data of each user through real-time response to the three-phase imbalance, and both the real-time performance and the efficiency are improved; the power consumption data may be data accumulated over a long period of time, and the efficiency of the regulation process at the current moment is improved by analyzing the long-term data.

Description

Technical Field

[0001] The invention relates to a method and a device for regulating three-phase imbalance in a low-voltage power supply line, belonging to the technical field of three-phase imbalance regulation. Background Art

[0002] Under ideal power consumption conditions, the currents of the three phases A / B / C of the power transmission and transformation lines and transformers are equal, the phase angle difference is 120°, the neutral line current is 0, the currents of the lines and distribution transformers are balanced, and there is no potential difference between the neutral line and the grounding line. This is the ideal power consumption state expected by the power supply company. Under such conditions, the output power efficiency is the highest, which can not only produce the best economic benefits, but also facilitate the safe operation of power supply lines and transformers.

[0003] The randomness of residents' electricity consumption makes the three-phase electricity consumption unbalanced. Unbalanced electricity consumption will cause energy loss; long-term unbalanced electricity consumption will lead to accelerated aging of power supply lines and transformers, and in extreme cases, it will cause major power outages. It is necessary to try to evenly distribute residents' electricity consumption. At present, there are many ways to measure whether the three phases are balanced by checking the electricity consumption of each resident in the three phases over a period of time. Although this method has a certain effect, it does not monitor the electricity consumption of residents in each period in real time, and cannot truly reflect whether the electricity consumption of residents is balanced, which greatly reduces the real-time adjustment of the three-phase imbalance. Summary of the invention

[0004] The object of the present invention is to provide a method and device for regulating three-phase imbalance in a low-voltage power supply line, so as to solve the problem of poor real-time performance of the three-phase imbalance regulation process existing in the prior art.

[0005] To achieve the above objectives, the present invention is implemented by adopting the following technical solutions:

[0006] In a first aspect, the present invention provides a method for regulating three-phase imbalance in a low-voltage power supply line, comprising:

[0007] In response to detecting that there is a three-phase imbalance in the low-voltage power supply line, obtaining power consumption data of each user in the low-voltage power supply line;

[0008] Calculate the best path for adjusting the user's electricity phase based on each user's electricity consumption data;

[0009] The power consumption phase of the user who needs to be adjusted in the low-voltage power supply line is adjusted according to the optimal path.

[0010] Furthermore, whether there is three-phase imbalance in the low-voltage power supply line is detected by the following method:

[0011] Obtain the three-phase current of each user in the low-voltage power supply line, and calculate the three-phase unbalance and the average current of the neutral line through the three-phase current of each user;

[0012] If the three-phase imbalance is greater than 15% and the average current of the neutral line is greater than the preset value, there is three-phase imbalance in the low-voltage power supply line.

[0013] Furthermore, the step of calculating the best path for adjusting the power consumption phase of each user according to the power consumption data of each user includes:

[0014] Swap the power phases of two phases of the three-phase current of a certain user, or swap the power phases of multiple users at a time, poll all user combinations and record the swap status of each swap, calculate the three-phase imbalance and the average neutral line current in the low-voltage power supply line after each swap, and use the swap status corresponding to the lowest three-phase imbalance and the lowest average neutral line current as the best path to adjust the user's power phase.

[0015] Furthermore, the three-phase imbalance is calculated by the following formula:

[0016] ;

[0017] in, is the three-phase average current, is the maximum average current of the three phases, is the minimum average current of the three-phase phase. It is the three-phase unbalance.

[0018] Furthermore, the average current of the neutral line is calculated by the following formula:

[0019] ;

[0020] in, is the average current in the neutral line, is the average current of phase A, is the average current of phase B, is the average current of phase C.

[0021] Furthermore, the three-phase average current is calculated by any one of the following three formulas:

[0022] ;

[0023] in, is the average current of phase A, is the average current of phase B, is the average current of phase C;

[0024] ;

[0025] Wherein, p is the active power of the single-phase energy meter used to test the current of each phase of the user, v is the voltage, v is 220V, n is the number of pulses of the single-phase energy meter within the preset time, and K is the meter constant of the single-phase energy meter;

[0026] ;

[0027] Where E is the single-phase energy meter reading, t is the time period for calculating the three-phase average current each time, and E now is the current reading of the single-phase energy meter, E b15min It is the single-phase energy meter reading 15 minutes ago.

[0028] In a second aspect, the present invention provides a device for regulating three-phase imbalance in a low-voltage power supply line, comprising: a regulating unit, a power recording and broadcasting controller, a phase-changing switch and an electric energy meter;

[0029] The power consumption recording and broadcasting controller is respectively connected to the phase-changing switch and the electric energy meter, the phase-changing switch is also connected to the electric energy meter, and the power consumption recording and broadcasting controller is connected to the regulating unit;

[0030] There are multiple electric energy meters, and each user in the low-voltage power supply line is connected to an electric energy meter. The electric energy meter sends the collected power consumption data of the user to the power consumption recording and broadcasting controller, and the power consumption recording and broadcasting controller sends the power consumption data to the adjustment unit. The adjustment unit performs any one of the above methods according to the power consumption data sent by the power consumption recording and broadcasting controller;

[0031] When the power consumption recording and broadcasting controller receives the adjustment instruction sent by the adjustment unit, the phase change action contained in the adjustment instruction is performed on the electric energy meter through the phase change switch to complete the adjustment of the user's power consumption phase.

[0032] Furthermore, it also includes a magnetic latching relay, wherein the magnetic latching relay is connected to the phase-changing switch and the electric energy meter;

[0033] The phase-changing action contained in the regulating instruction is executed on the electric energy meter through the phase-changing switch, comprising: the electric recording and broadcasting controller sends a phase-changing instruction corresponding to the phase-changing action to the magnetic holding relay through the phase-changing switch, and the magnetic holding relay executes the phase-changing action on the electric energy meter according to the phase-changing instruction.

[0034] Furthermore, the electric energy meter includes an electronic electric energy meter and a multi-rate electric energy meter.

[0035] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0036] The present invention provides a method and device for regulating three-phase imbalance in a low-voltage power supply line. By responding to the three-phase imbalance in real time, the optimal path for adjusting the user's power phase is found according to the power consumption data of each user, thereby improving the regulation efficiency of the three-phase imbalance, and both real-time performance and efficiency are improved; the power consumption data can be data accumulated over a long period of time, and the efficiency of the regulation process at the current moment can also be improved by analyzing the long-term data.

[0037] By installing an electricity recording and broadcasting controller at the user's location, the electricity consumption of each time-sharing electricity meter can be queried. The electricity pulse of each electronic electricity meter can also be queried through the switch input port, and the electricity consumption data of each user can be monitored. The monitored electricity consumption data can be reported to the adjustment unit. The adjustment unit counts the three-phase electricity consumption output by the low-voltage transformer in the low-voltage power supply line, calculates the three-phase imbalance, and based on the real-time electricity consumption data of all users over a period of time, the adjustment unit sends a certain / multiple user electricity phase adjustment command to the electricity recording and broadcasting controller based on the existing wiring distribution table of each user. The electricity recording and broadcasting controller controls the phase change switch action of the user who needs to be adjusted, and the user who needs to adjust the phase adjusts the phase to achieve a uniform distribution of the three-phase electricity consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flow chart of a method for adjusting three-phase imbalance in a low-voltage power supply line provided by an embodiment of the present invention;

[0039] Figure 2 is a schematic diagram of the connection between the electric energy meter and each phase current at a certain moment provided by an embodiment of the present invention;

[0040] Figure 3 It is a schematic diagram of a three-phase imbalance regulating device in a low-voltage power supply line provided by an embodiment of the present invention;

[0041] Figure 4 It is a schematic diagram of current statistics and regulation at a certain moment provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention.

[0043] Example 1.

[0044] like Figure 1 As shown, the present invention provides a method for regulating three-phase imbalance in a low-voltage power supply line, comprising the following steps:

[0045] In response to detecting that there is a three-phase imbalance in the low-voltage power supply line, obtaining power consumption data of each user in the low-voltage power supply line;

[0046] Calculate the best path for adjusting the user's electricity phase based on each user's electricity consumption data;

[0047] The power consumption phase of the user who needs to be adjusted in the low-voltage power supply line is adjusted according to the optimal path.

[0048] The present invention responds to three-phase imbalance in real time, finds the best path to adjust the user's power phase according to the power consumption data of each user, improves the regulation efficiency of the three-phase imbalance, and both real-time performance and efficiency are improved; the power consumption data can be data accumulated over a long period of time, and the efficiency of the regulation process at the current moment can also be improved by analyzing the long-term data.

[0049] Example 2.

[0050] like Figure 1 As shown, the present invention provides a method for regulating three-phase imbalance in a low-voltage power supply line, comprising the following steps:

[0051] S1. In response to detecting that there is a three-phase imbalance in a low-voltage power supply line, power consumption data of each user in the low-voltage power supply line is obtained.

[0052] In this embodiment, a residential community is taken as the object (low-voltage power supply line). The residential community has 6 buildings, each with three units, a total of 18 units, 12 households in each unit, a total of 216 households, and a 10kV / 315kW box-type transformer is installed. The meter box is installed in the corridor wall on the first floor, and the power consumption (power consumption data) of each household in the unit is collected through the power recording and broadcasting controller. The current statistics corresponding to the power demand of each unit in each building in the community for a certain 15 minutes under the low-voltage distribution transformer are as follows: Figure 4 shown.

[0053] pass Figure 4 The data in can be used to calculate the average neutral line current and three-phase imbalance of the residential area.

[0054] The specific calculation formula for the average current of the neutral line is:

[0055] =51A;

[0056] in, is the average current in the neutral line, is the average current of phase A, is the average current of phase B, is the average current of phase C.

[0057] The specific calculation formula for three-phase unbalance is:

[0058] =19%;

[0059] in, is the three-phase average current, is the maximum average current of the three phases, is the minimum average current of the three-phase phase. It is the three-phase unbalance.

[0060] The specific calculation formula of the three-phase average current in this embodiment is:

[0061] ;

[0062] in, is the average current of phase A, is the average current of phase B, is the average current of phase C.

[0063] If the power consumption data collected by different types of energy meters are different, the three-phase average current can also be calculated using any of the following two formulas:

[0064] ;

[0065] Wherein, p is the active power of the single-phase energy meter used to test the current of each phase of the user, v is the voltage, v is 220V, n is the number of pulses of the single-phase energy meter within a preset time (15 minutes in this embodiment), and K is the meter constant of the single-phase energy meter;

[0066] ;

[0067] Where E is the single-phase energy meter reading, t is the time period for calculating the three-phase average current each time, and E now is the current reading of the single-phase energy meter, E b15min It is the single-phase energy meter reading 15 minutes ago.

[0068] The transformer capacity is 315kW, the rated current of each phase is 315 / 3 / 220=477A, ​​and the maximum current of light load is 477×30%=143A. At this time, the three-phase current exceeds 143A, which is not a light load.

[0069] The criterion for determining whether there is three-phase imbalance is: if the three-phase imbalance is greater than 15%, and the average current of the neutral line is greater than a preset value (5% in this embodiment), there is three-phase imbalance in the low-voltage power supply line.

[0070] By calculating the average neutral line current and the three-phase imbalance, it can be determined that the residential community currently has a three-phase imbalance.

[0071] S2. Calculate the best path for adjusting the user's electricity consumption phase based on the electricity consumption data of each user.

[0072] Step S2 is implemented by the following specific method: swapping the power phases of two phases of the three-phase current of a certain user (in this embodiment, one unit is one user), or swapping the power phases of multiple users at a time, polling all user combinations and recording the swap conditions of each swap, calculating the three-phase imbalance and the average neutral line current in the low-voltage power supply line after each swap is completed, and taking the swap condition corresponding to the lowest three-phase imbalance and the lowest average neutral line current as the optimal path for adjusting the user's power phase.

[0073] Through calculation, we know that by swapping phase A and phase B of unit 2 in building 1, and phase A and phase C of unit 2 in building 4, after this swap, the average current of the neutral line drops to 4.3A, and the three-phase imbalance drops to 1.7%. Both the average current of the neutral line and the three-phase imbalance can meet the three-phase balance standard. This swap is regarded as the best path.

[0074] S3. Adjust the power consumption phase of the user who needs to be adjusted in the low-voltage power supply line according to the optimal path.

[0075] According to the best path calculated in step S2 (such as Figure 4 (As shown in the swapping situation, phase A of unit 2 in building 1 in the residential community is swapped with phase B, and phase A of unit 2 in building 4 is swapped with phase C to complete the three-phase unbalanced adjustment.

[0076] Example 3.

[0077] like Figure 3 As shown, the present invention provides a three-phase imbalance regulating device in a low-voltage power supply line, including a regulating unit, a power recording and broadcasting controller, a phase-changing switch, a magnetic latching relay and an electric energy meter, wherein the electric energy meter is divided into an electronic electric energy meter and a multi-rate electric energy meter.

[0078] Figure 3 In the figure, there are n electronic energy meters, namely electronic energy meter 1, electronic energy meter 2, ..., electronic energy meter n, and there are also n multi-rate energy meters, namely multi-rate energy meter 1, multi-rate energy meter 2, ..., multi-rate energy meter n.

[0079] The adjustment unit is connected to the power consumption recording and broadcasting controllers of unit 1 of building 1, unit 2 of building 1, ..., unit n of building n through the 4G network. This embodiment is described by taking unit 1 of building 1 as an example.

[0080] In unit 1 of building 1, the electricity consumption recording and broadcasting controller is directly connected to multi-rate electricity meter 1, multi-rate electricity meter 2, ..., multi-rate electricity meter n through RS-485, and the electricity consumption recording and broadcasting controller is directly connected to electronic electricity meter 1, electronic electricity meter 2, ..., electronic electricity meter n through pulses. Each electricity meter transmits the collected electricity consumption data to the electricity consumption recording and broadcasting controller in real time, and the electricity consumption recording and broadcasting controller sends it to the adjustment unit. The adjustment unit executes the method provided in Example 1 / Example 2 according to the acquired electricity consumption data.

[0081] To facilitate meter calibration, the single-phase electronic energy meter (in this embodiment, all energy meters are single-phase energy meters) has a pulse output port, which is output through optocoupler isolation. The single-phase multi-rate energy meter not only has a pulse output port, but also an isolated RS-485 communication port. The communication protocol generally adopts the multi-function energy meter communication protocol of DLT645 / 1997 or DLT645 / 2007 issued by the Ministry of Electric Power, or its variant version. DLT645 / 1997 stipulates that the communication rate is 1200bps, while DLT645 / 2007 stipulates that the communication rate is 2400bps. Some energy meters can read the current maximum demand (15-minute average power), while some cannot read the maximum demand. The maximum demand can be calculated by reading the current electricity meter reading and the electricity meter reading 15 minutes ago.

[0082] When the adjustment unit executes the method provided in Embodiment 1 / Embodiment 2, it is necessary to calculate the three-phase average current, which can be calculated by the following formula:

[0083] If the number of pulses of a single-phase energy meter in 15 minutes is n, the meter constant is K, and the voltage v is 220V, then the 15-minute three-phase average current is calculated by the following formula:

[0084] ;

[0085] Among them, p is the active power of the single-phase electric energy meter used to test the current of each phase of the user, v is the voltage, v is 220V, n is the number of pulses of the single-phase electric energy meter within a preset time (15 minutes in this embodiment), and K is the meter constant of the single-phase electric energy meter.

[0086] If a single-phase energy meter reads the current reading and the reading 15 minutes ago through RS-485, and the voltage v is 220V, then its 15-minute three-phase average current can also be calculated using the following formula:

[0087] ;

[0088] Where E is the single-phase energy meter reading, t is the time period for calculating the three-phase average current each time, and E now is the current reading of the single-phase energy meter, E b15min It is the single-phase energy meter reading 15 minutes ago.

[0089] In this embodiment, the connection relationship between the electric energy meter and each phase current is as follows: Figure 2 As shown, the unit of each number in the figure is kwh.

[0090] The host of the power recording and broadcasting controller has an RS-485 interface, which can communicate with up to 16 single-phase multi-rate electricity meters, collect the maximum demand of the electricity meter for 15 minutes, read the electricity indication number, and calculate the average current of each electricity meter for 15 minutes. The power recording and broadcasting controller also has 16 external event interrupt input ports, which can monitor up to 16 electronic electricity meter pulses at the same time, and use the 15-minute pulse number to calculate the average current of each electricity meter for 15 minutes. The communication mode and external event entry used by each electricity meter, the pulse constant of the electricity meter, and the phase of the electricity meter can be set through the keypad of the power recording and broadcasting controller, so that the three-phase imbalance rate under the device can be calculated and monitored. The power recording and broadcasting controller also has a 4G communication module, which communicates with the adjustment unit through the 4G network and reports the monitored three-phase current to the adjustment unit.

[0091] In Unit 1 of Building 1, the power recording and broadcasting controller is also connected to n phase-changing switches, each of which is connected to a magnetic latching relay (large capacity). The phase-changing switch switches the phase of the energy meter through the magnetic latching relay, thereby switching the user's power phase. The phase-changing switch and the magnetic latching relay are controlled by the power recording and broadcasting controller. From the ABC phase incoming lines, one phase is selected to power the single-phase energy meter. The magnetic latching relay has a very short action time and can be controlled to switch the phase at the current zero point. The time control is completed within 2mS, which does not affect the normal power consumption of users.

[0092] The specific adjustment process of the three-phase imbalance adjustment device in a low-voltage power supply line provided in this embodiment can be summarized as follows: the electric energy meter sends the collected user's electricity consumption data to the electricity consumption recording and broadcasting controller, the electricity consumption recording and broadcasting controller sends the electricity consumption data to the adjustment unit, and the adjustment unit executes the method provided in Example 1 / Example 2 according to the electricity consumption data sent by the electricity consumption recording and broadcasting controller; when the electricity consumption recording and broadcasting controller receives the adjustment instruction sent by the adjustment unit, the phase change action contained in the adjustment instruction is executed on the electric energy meter through the phase change switch to complete the adjustment of the user's electricity consumption phase.

[0093] The power recording and broadcasting controller executes the phase change action contained in the adjustment instruction on the electric energy meter through the phase change switch, specifically including: the power recording and broadcasting controller sends the phase change instruction corresponding to the phase change action to the magnetic holding relay through the phase change switch, and the magnetic holding relay executes the phase change action on the electric energy meter according to the phase change instruction.

[0094] The regulating unit can summarize, count and calculate the real-time data monitored by the power consumption recording and broadcasting controller of each building and each unit to determine whether the three phases are balanced. It can also find the minimum way to adjust the user's phase sequence based on the power consumption information of half a year or a year, so that the three-phase power consumption is basically equal under the low-voltage transformer.

[0095] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0096] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0097] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0098] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0099] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for regulating three-phase imbalance in a low-voltage power supply line, characterized in that: include: In response to detecting that there is a three-phase imbalance in the low-voltage power supply line, obtaining power consumption data of each user in the low-voltage power supply line; Calculate the best path for adjusting the user's electricity phase based on each user's electricity consumption data; Adjusting the power consumption phase of the user who needs to be adjusted in the low-voltage power supply line according to the optimal path; Whether there is three-phase imbalance in the low-voltage power supply line is detected by the following method: Obtain the three-phase current of each user in the low-voltage power supply line, and calculate the three-phase imbalance and the average current of the neutral line through the three-phase current of each user; If the three-phase unbalance is greater than 15% and the average current of the neutral line is greater than the preset value, there is a three-phase unbalance in the low-voltage power supply line; The step of calculating the best path for adjusting the power phase of each user according to the power consumption data of each user includes: Swap the power phases of two phases of the three-phase current of a certain user, or swap the power phases of multiple users at a time, poll all user combinations and record the swap situation of each swap, calculate the three-phase imbalance and the average current of the neutral line in the low-voltage power supply line after each swap, and use the swap situation corresponding to the lowest three-phase imbalance and the average current of the neutral line as the best path to adjust the power phase of the user; The three-phase unbalance is calculated by the following formula: ； in, is the three-phase average current, is the maximum average current of the three phases, is the minimum average current of the three-phase phase. is the three-phase unbalance; The average current of the neutral line is calculated by the following formula: ； in, is the average current in the neutral line, is the average current of phase A, is the average current of phase B, is the average current of phase C; The three-phase average current is calculated by any one of the following three formulas: ； ； Wherein, p is the active power of the single-phase energy meter used to test the current of each phase of the user, v is the voltage, v is 220V, n is the number of pulses of the single-phase energy meter within the preset time, and K is the meter constant of the single-phase energy meter; ； Where E is the single-phase energy meter reading, t is the time period for calculating the three-phase average current each time, and E now is the current reading of the single-phase energy meter, E b15min It is the single-phase energy meter reading 15 minutes ago.

2. A device for regulating three-phase imbalance in a low-voltage power supply line, characterized in that: include: Regulation unit, power consumption recording and broadcasting controller, phase change switch and energy meter; The power consumption recording and broadcasting controller is respectively connected to the phase-changing switch and the electric energy meter, the phase-changing switch is also connected to the electric energy meter, and the power consumption recording and broadcasting controller is connected to the regulating unit; The electric energy meter is provided with a plurality of electric energy meters, and each user in the low-voltage power supply line is connected to an electric energy meter, the electric energy meter sends the collected electric consumption data of the user to the electric consumption recording and broadcasting controller, the electric consumption recording and broadcasting controller sends the electric consumption data to the regulating unit, and the regulating unit executes the method according to claim 1 according to the electric consumption data sent by the electric consumption recording and broadcasting controller; When the power consumption recording and broadcasting controller receives the adjustment instruction sent by the adjustment unit, the phase change action contained in the adjustment instruction is performed on the electric energy meter through the phase change switch to complete the adjustment of the user's power consumption phase.

3. The device for regulating three-phase imbalance in a low-voltage power supply line according to claim 2, characterized in that: It also includes a magnetic latching relay, which connects the phase-changing switch and the electric energy meter; The phase-changing action contained in the regulating instruction is executed on the electric energy meter through the phase-changing switch, comprising: the electric recording and broadcasting controller sends a phase-changing instruction corresponding to the phase-changing action to the magnetic holding relay through the phase-changing switch, and the magnetic holding relay executes the phase-changing action on the electric energy meter according to the phase-changing instruction.

4. The device for regulating three-phase imbalance in a low-voltage power supply line according to claim 2, characterized in that: The electric energy meter includes an electronic electric energy meter and a multi-rate electric energy meter.

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