A method and system for metering power loss during replacement of an electricity meter

Abstract

The application discloses a kind of electric energy meter replacement period electric quantity loss metering method and system, first determine the electric voltage test loop quantity involved in electric quantity metering of the electric energy meter to be replaced, and configure the pair of current transformer clamp and single-phase electric energy meter for each electric voltage test loop;The pair of current transformer clamp is respectively clamped to the current input line, output line of each electric voltage test loop high voltage phase, and the single-phase electric energy meter is connected to the secondary winding of corresponding current transformer clamp;Then, the secondary winding of high-voltage current transformer connected to the electric energy meter to be replaced is short-circuited, and the power consumption wh1 on the single-phase electric energy meter at this stage is recorded;The electric energy meter to be replaced is removed, and the power consumption wh2 on the single-phase electric energy meter at this stage is recorded;New electric energy meter is connected to joint terminal box, and the power consumption wh3 on the single-phase electric energy meter at this stage is recorded;Finally, the power consumption loss during electric energy meter replacement is calculated according to wh1, wh2 and wh3.The application is more efficient and safer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric quantity measurement, and particularly relates to a method and system for measuring electric quantity loss during replacement of an electric energy meter. BACKGROUND

[0002] With the construction of the electric power spot market, power supply companies begin to popularize and apply flexible rate electric energy meters. At present, the power supply company has only completed the replacement of electric energy meters of part of large industrial users, and will promote the batch replacement of all high-voltage user metering electric energy meters in the later period. During the replacement of the electric energy meter, the old electric energy meter needs to be removed, which will cause a period of non-metering state, and the duration of this state is generally more than 15 minutes according to statistics. Although there is electric quantity loss during the replacement of the electric energy meter of a small electric quantity user, the electric quantity is not large, and the effect is small. However, for high-voltage large load users, the loss of electric quantity during the replacement of the electric energy meter is more than 10,000 kWh, and there will be a large amount of error electric quantity, and it will be difficult to coordinate the electric quantity refund with the customer. Taking a double-circuit power supply steel plant as an example, the load power of the two lines is about 80,000 kW, and the loss of electric quantity during the replacement of the electric energy meter (calculated at 15 minutes) is about 20,000 kWh.

[0003] At present, the replacement of the high-voltage metering device has the following difficulties in the refund of the loss of electric quantity: (1) The data is difficult to obtain in real time, and the calculation accuracy is low. The conventional refund of electric quantity generally needs to be calculated by professional technical personnel after the replacement of the electric energy meter. According to the requirements of the metering device installation and removal operation instruction, the electric quantity during the non-metering period is roughly calculated by recording the instantaneous power before the replacement of the electric energy meter and the time before and after the replacement of the electric energy meter. Because the power of the customer changes in real time, the calculation accuracy of this scheme is greatly affected by the load fluctuation. (2) The on-site work relies on manual work, and the automatic level of the equipment needs to be improved. At present, when the metering personnel perform on-site replacement, the replacement base data recording sheet and the loss of electric quantity refund sheet are mainly recorded manually, and there is a risk of missing or misreporting the replacement base data, which needs to be repeatedly audited by a special person, and the work efficiency is low, the labor cost is high, and there is a lack of automatic base data input, loss of electric quantity recording and work order printing equipment.

[0004] Therefore, researchers have studied the measurement of electricity loss. For example, patent application number 201611015234 discloses a method for replacing an electricity meter without power interruption using a standard meter. This method connects a standard meter to the meter circuit. During the process from the removal of the old electricity meter to the installation of the new electricity meter, the electricity metering circuit is built by switching the short-circuit plate in the electricity metering device, and the electricity metering is realized during the meter replacement process using the standard meter. However, since electricity metering devices usually have anti-theft and anti-electricity theft functions, the secondary terminals of the voltage transformer, the secondary terminals of the current transformer, the junction box, and the electricity meter are all sealed with covers and lead seals. There are no other exposed measurement points. Therefore, when connecting the standard meter to the junction box, voltage measurement must be connected to the voltage terminal of the junction box. Connecting to the voltage terminal is cumbersome and requires the use of a screwdriver. The junction box space is small, which limits the operation space and affects the meter replacement efficiency. In addition, an insecure connection to the terminal can also affect safety. Summary of the Invention

[0005] This invention provides a method and system for measuring electricity loss during electricity meter replacement, in order to solve the problem of inconvenient electricity loss measurement during electricity meter replacement in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for measuring electricity loss during electricity meter replacement, the process is as follows:

[0008] Determine the number of voltage test circuits on the junction box involved in the metering of the electricity meter to be replaced;

[0009] Each voltage test circuit is configured with a clamp-on current transformer pair and a single-phase energy meter, wherein the clamp-on current transformer pair includes a first clamp-on current transformer and a second clamp-on current transformer.

[0010] Clamp the first clamp-on current transformer to the current input line of the high-voltage phase in the corresponding voltage test circuit on the junction box, clamp the second clamp-on current transformer to the current output line of the high-voltage phase in the corresponding voltage test circuit on the junction box, and connect the secondary output windings of the first clamp-on current transformer and the second clamp-on current transformer corresponding to each voltage test circuit in parallel with opposite polarities.

[0011] The voltage input end of the single-phase electric energy meter is connected to the input connection terminal of the high-voltage phase in the corresponding voltage test loop of the joint terminal box, the voltage output end of the single-phase electric energy meter is connected to the input connection terminal of the low-voltage phase in the corresponding voltage test loop of the joint terminal box, the current input end of the single-phase electric energy meter is connected to the first connection point of the secondary output windings of the corresponding first and second clamp current transformers, and the current output end of the single-phase electric energy meter is connected to the second connection point of the secondary output windings of the corresponding first and second clamp current transformers.

[0012] The current short-circuit piece of the joint terminal box is moved to short-circuit the secondary winding of the high-voltage current transformer connected to the electric energy meter to be replaced, and the power consumption sensed by the single-phase electric energy meter at this time is recorded as wh1.

[0013] Then, the electric energy meter to be replaced is removed, and the power consumption sensed by the single-phase electric energy meter at this time is recorded as wh2.

[0014] Then, the new electric energy meter is connected to the joint terminal box, the current short-circuit piece of the joint terminal box is moved to connect the new electric energy meter to the secondary winding of the high-voltage current transformer, the replacement of the electric energy meter is completed, and the power consumption sensed by the single-phase electric energy meter at this time is recorded as wh3.

[0015] Finally, the power loss wh during the replacement of the electric energy meter is calculated, as shown in the following formula:

[0016] wh = wh1 + wh2 + wh3.

[0017] Further, if the electric energy meter to be replaced is a three-phase three-wire electric energy meter including three phase lines, the number of voltage test loops on the joint terminal box involved is 2, which are CB phase voltage test loop and AB phase voltage test loop.

[0018] If the electric energy meter to be replaced is a three-phase four-wire electric energy meter including three phase lines and one neutral line, the number of voltage test loops on the joint terminal box involved is 3, which are AN voltage test loop, BN voltage test loop and CN voltage test loop.

[0019] Further, when the electric energy meter to be replaced is a three-phase three-wire electric energy meter including three phase lines, the CB phase voltage test loop takes C phase as high-voltage phase and B phase as low-voltage phase, and the AB phase voltage test loop takes A phase as high-voltage phase and B phase as low-voltage phase.

[0020] When the electric energy meter to be replaced is a three-phase four-wire electric energy meter including three phase lines and one neutral line, the AN voltage test loop takes A phase as high-voltage phase and N as low-voltage phase, the BN voltage test loop takes B phase as high-voltage phase and N as low-voltage phase, and the CN voltage test loop takes C phase as high-voltage phase and N as low-voltage phase.

[0021] Further, the first and second current transformers in each pair of current transformers have the same current ratio and consistent error.

[0022] Further, the single-phase electric energy meter is a power electric energy standard meter.

[0023] An electric energy meter replacement period electric quantity loss metering system for implementing the above-mentioned electric energy meter replacement period electric quantity loss metering method comprises a pair of current transformers and a single-phase electric energy meter for each voltage test loop of a joint terminal box involved in electric quantity metering of a to-be-replaced electric energy meter, wherein the pair of current transformers comprises a first current transformer and a second current transformer.

[0024] The first current transformer is clamped to a current input line of a high-voltage phase in the corresponding voltage test loop of the joint terminal box, the second current transformer is clamped to a current output line of the high-voltage phase in the corresponding voltage test loop of the joint terminal box, and the secondary output windings of the first and second current transformers of each voltage test loop are reversely connected in parallel.

[0025] The voltage input end of the single-phase electric energy meter is connected to an input connection terminal of a high-voltage phase in the corresponding voltage test loop of the joint terminal box, the voltage output end of the single-phase electric energy meter is connected to an input connection terminal of a low-voltage phase in the corresponding voltage test loop of the joint terminal box, the current input end of the single-phase electric energy meter is connected to a first connection point of the secondary output windings of the corresponding first and second current transformers, and the current output end of the single-phase electric energy meter is connected to a second connection point of the secondary output windings of the corresponding first and second current transformers.

[0026] Further, the system further comprises an electric quantity metering module connected to the single-phase electric energy meter.

[0027] The electric quantity metering module records an electric quantity wh1 sensed by the single-phase electric energy meter during a stage in which the current short-circuit piece of the joint terminal box is moved to short-circuit the secondary windings of the high-voltage current transformer to which the to-be-replaced electric energy meter is connected.

[0028] The electric quantity metering module records an electric quantity wh2 sensed by the single-phase electric energy meter during a stage in which the to-be-replaced electric energy meter is removed.

[0029] The electric quantity metering module records an electric quantity wh3 sensed by the single-phase electric energy meter during a stage in which the joint terminal box is moved to connect the new electric energy meter to the secondary windings of the high-voltage current transformer after the new electric energy meter is connected to the joint terminal box.

[0030] The electric quantity loss wh during the electric energy meter replacement period is calculated by the electric quantity metering module based on the formula wh= wh1+ wh2 +wh3.

[0031] Further, the first and second current transformers in each pair of current transformers have the same current ratio and consistent error.

[0032] Further, the single-phase electric energy meter is a power electric energy standard meter. Compared with the prior art, the present application has the beneficial effects that: the present application clamps the current input line and the current output line of the joint terminal box by the current transformer, and connects the secondary winding of the current transformer to the electric energy meter, thereby realizing current detection and obtaining the electric quantity loss. The present application has low requirements for operation space, is simple to operate, and has higher meter replacement efficiency. In addition, the current transformer is firmly connected and is not easy to fall off, and even if it falls off, it will not cause a safety accident. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a flowchart of the electric quantity loss metering method during electric energy meter replacement provided by the present embodiment.

[0034] Figure 2 is a circuit schematic diagram of the CB phase voltage test circuit in the first case in the present application.

[0035] Figure 3 is a circuit schematic diagram of the CB phase voltage test circuit in the second case in the present application.

[0036] Figure 4 is a circuit schematic diagram of the CB phase voltage test circuit in the third case in the present application.

[0037] Figure 5 is a circuit schematic diagram of the CB phase voltage test circuit in the fourth case in the present application.

[0038] Figure 6 is a circuit schematic diagram of the CB phase voltage test circuit in the fifth case in the present application. DETAILED DESCRIPTION

[0039] The present application is further described below in combination with the drawings and embodiments.

[0040] Embodiment One

[0041] As shown in the drawings, the present embodiment provides an electric quantity loss metering method during electric energy meter replacement, comprising the following steps: Figure 1

[0042] ​Step 1, determine the number of voltage test circuits on the joint junction box involved in the electric quantity measurement of the electric energy meter to be replaced. Specifically, if the electric energy meter to be replaced is a three-phase three-wire electric energy meter including three phase lines, the number of voltage test circuits is 2, which are CB phase voltage test circuit and AB phase voltage test circuit. If the electric energy meter to be replaced is a three-phase four-wire electric energy meter including three phase lines and one neutral line, the number of voltage test circuits is 3, which are AN voltage test circuit, BN voltage test circuit and CN voltage test circuit.

[0043] A pair of clamp-on current transformers and a single-phase electric energy meter are configured for each voltage test circuit, wherein the pair of clamp-on current transformers includes a first clamp-on current transformer and a second clamp-on current transformer, the first clamp-on current transformer and the second clamp-on current transformer have the same current ratio and consistent error. The single-phase electric energy meter is a power electric energy standard meter.

[0044] Step 2, for each pair of clamp-on current transformers, the first clamp-on current transformer is clamped to the current input line of the high-voltage phase on the corresponding voltage test circuit of the joint junction box, and the second clamp-on current transformer is clamped to the current output line of the high-voltage phase on the corresponding voltage test circuit of the joint junction box, and the secondary output windings of the first clamp-on current transformer and the second clamp-on current transformer of each voltage test circuit are connected in reverse polarity in parallel.

[0045] When the electric energy meter to be replaced is a three-phase three-wire electric energy meter including three phase lines, the CB phase voltage test circuit takes C phase as the high-voltage phase and B phase as the low-voltage phase; the AB phase voltage test circuit takes A phase as the high-voltage phase and B phase as the low-voltage phase.

[0046] When the electric energy meter to be replaced is a three-phase four-wire electric energy meter including three phase lines and one neutral line, the AN voltage test circuit takes A phase as the high-voltage phase and N as the low-voltage phase; the BN voltage test circuit takes B phase as the high-voltage phase and N as the low-voltage phase; the CN voltage test circuit takes C phase as the high-voltage phase and N as the low-voltage phase.

[0047] Assuming that the electric energy meter to be replaced is a three-phase three-wire electric energy meter, for the CB phase voltage test circuit, the connection mode of the corresponding pair of clamp-on current transformers is as shown in Figure 2 The high-voltage phase in the CB phase voltage test circuit is C phase and the low-voltage phase is B phase. Under the condition that the user does not stop power supply, the high-voltage current is converted into low-voltage current by the high-voltage current transformer, the secondary current ic2 is output from the secondary winding of the high-voltage current transformer according to the current ratio, and is input to the electric energy meter to be replaced WH1 through the joint junction box JB. The first clamp-on current transformer TA1 is clamped to the C phase current input line of the joint junction box JB, the second clamp-on current transformer TA2 is clamped to the C phase current output line of the joint junction box JB, and the secondary output windings of the first clamp-on current transformer TA1 and the second clamp-on current transformer TA2 are connected in reverse polarity in parallel.

[0048] Step 3, connect the voltage input end of the single-phase electric energy meter to the input connection terminal of the high-voltage phase in the corresponding voltage test loop of the joint terminal box, connect the voltage output end of the single-phase electric energy meter to the input connection terminal of the low-voltage phase in the corresponding voltage test loop of the joint terminal box, connect the current input end of the single-phase electric energy meter to the first connection point of the secondary output windings of the corresponding first and second clamp current transformers, and connect the current output end of the single-phase electric energy meter to the second connection point of the secondary output windings of the corresponding first and second clamp current transformers.

[0049] As shown in Figure 2 , for the CB phase voltage test loop, connect the voltage input end of the single-phase electric energy meter WH2 to the C-phase input connection terminal Uc of the joint terminal box JB, connect the voltage output end to the B-phase input connection terminal Ub of the joint terminal box JB, connect the current input end to the first connection point of the secondary output windings of the first and second clamp current transformers TA1 and TA2, and connect the current output end to the second connection point of the secondary output windings of the first and second clamp current transformers TA1 and TA2. The other AB phase voltage test loops are connected in the same way.

[0050] If the electric energy meter to be replaced is a three-phase four three-wire electric energy meter, then the AN, BN, and CN voltage test loops are connected in the manner of steps 2 and 3, respectively.

[0051] After the connection is completed, for the CB phase voltage test loop, the C-phase input current is equal to the C-phase output current at this time, and the two clamp current transformers are testing the same current ic2. Since the polarities are opposite, the TA1 output current TA1_ic2 and the TA2 output current TA2_ic2 are equal in size and opposite in direction. The two secondary currents are superimposed to be zero on the single-phase electric energy meter ic0. At this time, the electric energy meter to be replaced WH1 will continue to normally meter the electric energy, and the electric energy meter WH2 at this time meters 0.

[0052] Step 4, move the current short-circuit piece of the joint terminal box to short-circuit the secondary windings of the high-voltage current transformer connected to the electric energy meter to be replaced, and record the electric energy wh1 sensed by the single-phase electric energy meter at this stage.

[0053] As shown in Figure 2 , during actual user power consumption, the high-voltage three-phase power (UVW three wires) is high-voltage, which is converted into low-voltage power by the high-voltage current transformer, outputs the secondary current ic2, and is connected to the electric energy meter WH1 through the joint terminal box JB before reaching the user's residence. The secondary windings of the high-voltage current transformer in this embodiment are the windings on the user side, and the primary windings are on the high-voltage side.

[0054] AsFigure 3 As shown, for the CB phase voltage test circuit, the first clamp-on current transformer TA1 measures the secondary current shunt ic2, while the second clamp-on current transformer TA2 measures the CT secondary current shunt ic3. At this time, WH1 can test the CT secondary current shunt ic3. Generally, ic3 is much smaller than ic2, and in most cases, ic3 can be considered to be 0. At this time, the power consumption base wh0 on WH1 can be recorded. During this stage, the current on WH2 is ic0 = TA1_ic2 - TA2_ic3, and the power consumption wh1 on WH2 is recorded.

[0055] Step 5: Remove the electricity meter to be replaced and record the electricity consumption (wh2) sensed on the single-phase electricity meter at this stage.

[0056] like Figure 4 As shown, for the CB phase voltage test circuit, at this time, the first clamp current transformer TA1 measures all the secondary currents ic2 of the CT, while the second clamp current transformer TA2 measures the current ic3 as zero. The output current of TA2 is TA2_ic3=0. During this stage, WH2 measures all the secondary currents of the C phase, ic0=TA1_ic2. Record the power consumption wh2 on WH2 during this stage.

[0057] Step 6: Connect the new energy meter to the junction box, move the current shorting piece of the junction box to connect the new energy meter to the secondary winding of the high-voltage current transformer, and complete the energy meter replacement. Record the electricity consumption wh3 sensed by the single-phase energy meter at this stage.

[0058] like Figure 5 As shown, for the CB phase voltage test circuit, there is also a small amount of power loss when the new energy meter WH3 is connected to the junction box JB. Record the power consumption wh3 on WH2 during this period. Move the current shorting piece of WH2, as follows: Figure 6 As shown, this connects the new energy meter to the secondary winding of the high-voltage current transformer. All the secondary current of the high-voltage current transformer passes through the new energy meter WH3. At this time, since the output currents of TA1 and TA2 are superimposed and equal to 0, WH2 consumes no electricity during this stage.

[0059] Step 7: Calculate the energy loss wh = wh1 + wh2 + wh3 during the energy meter replacement period, and update the reading of the new energy meter WH3 to wh0 + wh.

[0060] Example 2

[0061] The embodiment of the present application provides a power meter replacement period electric quantity loss metering system for realizing the power meter replacement period electric quantity loss metering method, which comprises an electric quantity metering module, and a number of pairs of clamp current transformers and single-phase electric energy meters equal to the number of voltage test loop circuits of a joint terminal box related to electric quantity metering of a power meter to be replaced, i.e. one pair of clamp current transformers and one single-phase electric energy meter are configured for each voltage test loop circuit.

[0062] In each pair of clamp current transformers, the first clamp current transformer is clamped to the current input line of the high-voltage phase of the corresponding voltage test loop circuit of the joint terminal box, and the second clamp current transformer is clamped to the current output line of the high-voltage phase of the corresponding voltage test loop circuit of the joint terminal box, and the secondary output windings of the first clamp current transformer and the second clamp current transformer corresponding to each voltage test loop circuit are reversely connected in parallel.

[0063] The voltage input end of each single-phase electric energy meter is connected to the input connection terminal of the high-voltage phase of the corresponding voltage test loop circuit of the joint terminal box, the voltage output end of each single-phase electric energy meter is connected to the input connection terminal of the low-voltage phase of the corresponding voltage test loop circuit of the joint terminal box, the current input end of each single-phase electric energy meter is connected to the first connection point of the secondary output windings of the corresponding first clamp current transformer and second clamp current transformer, and the current output end of each single-phase electric energy meter is connected to the second connection point of the secondary output windings of the corresponding first clamp current transformer and second clamp current transformer.

[0064] The electric quantity metering module records the electric quantity wh1 on the single-phase electric energy meter in the stage of short-circuiting the secondary windings of the high-voltage current transformer connected to the power meter to be replaced by moving the current short-circuiting piece of the joint terminal box, records the electric quantity wh2 on the single-phase electric energy meter in the stage of removing the power meter to be replaced, and records the electric quantity wh3 on the single-phase electric energy meter in the stage of connecting the new power meter to the joint terminal box and connecting the new power meter to the secondary windings of the high-voltage current transformer by moving the current short-circuiting piece of the joint terminal box.

[0065] Finally, the electric quantity loss during the replacement of the power meter is calculated by the electric quantity loss calculation module based on the formula wh= wh1+ wh2 +wh3.

[0066] If the electric energy meter to be replaced is a single-phase electric energy meter including one phase line and one neutral line, the number of voltage test loops of the electric energy meter to be replaced is 1; if the electric energy meter to be replaced is a three-phase three-wire electric energy meter including three phase lines, the number of voltage test loops of the electric energy meter to be replaced is 2, which are a CB phase voltage test loop and an AB phase voltage test loop; if the electric energy meter to be replaced is a three-phase four-wire electric energy meter including three phase lines and one neutral line, the number of voltage test loops of the electric energy meter to be replaced is 3, which are an AN voltage test loop, a BN voltage test loop and a CN voltage test loop. In the CB phase voltage test loop, the C phase is a high-voltage phase and the B phase is a low-voltage phase; in the AB phase voltage test loop, the A phase is a high-voltage phase and the B phase is a low-voltage phase; in the AN voltage test loop, the A phase is a high-voltage phase and the N phase is a low-voltage phase; in the BN voltage test loop, the B phase is a high-voltage phase and the N phase is a low-voltage phase; and in the CN voltage test loop, the C phase is a high-voltage phase and the N phase is a low-voltage phase.

[0067] In each pair of the clamp-on current transformers, the first clamp-on current transformer and the second clamp-on current transformer have the same current ratio and consistent error. The single-phase electric energy meter is a power electric energy standard meter.

[0068] It should be noted that the relational terms such as first and second are used only to differentiate one entity or operation from another, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations.

[0069] It should be understood that the above embodiments and the description in the specification are only the principles, main features and advantages of the present application, and various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the protection scope of the present application.

Claims

1. A method for metering the loss of electricity during the replacement of an electricity meter, characterized in that, The process is as follows: Determine the number of voltage test circuits on the joint terminal block involved in the electric energy meter electric quantity measurement; Configure a pair of clamp current transformers and a single-phase electric energy meter for each voltage test circuit, wherein the pair of clamp current transformers includes a first clamp current transformer and a second clamp current transformer; Clamp the first clamp current transformer to the current input line of the high-voltage phase on the corresponding voltage test circuit of the joint terminal block, clamp the second clamp current transformer to the current output line of the high-voltage phase on the corresponding voltage test circuit of the joint terminal block, and connect the secondary output windings of the first clamp current transformer and the second clamp current transformer in each voltage test circuit in reverse polarity in parallel; Connect the voltage input end of the single-phase electric energy meter to the input connection terminal of the high-voltage phase on the corresponding voltage test circuit of the joint terminal block, connect the voltage output end of the single-phase electric energy meter to the input connection terminal of the low-voltage phase on the corresponding voltage test circuit of the joint terminal block, connect the current input end of the single-phase electric energy meter to the first connection point of the secondary output windings of the corresponding first clamp current transformer and second clamp current transformer, and connect the current output end of the single-phase electric energy meter to the second connection point of the secondary output windings of the corresponding first clamp current transformer and second clamp current transformer; Move the current short-circuit piece of the joint terminal block to short-circuit the secondary winding of the high-voltage current transformer connected to the electric energy meter to be replaced, and record the electric quantity sensed on the single-phase electric energy meter at this time, wh1; Next, remove the electric energy meter to be replaced, and record the electric quantity sensed on the single-phase electric energy meter at this time, wh2; Then, connect the new electric energy meter to the joint terminal block, move the current short-circuit piece of the joint terminal block, connect the new electric energy meter to the secondary winding of the high-voltage current transformer, complete the replacement of the electric energy meter, and record the electric quantity sensed on the single-phase electric energy meter at this time, wh3; Finally, calculate the electric quantity loss wh during the replacement of the electric energy meter, as shown in the following formula: wh= wh1+ wh2 +wh3.

2. The method according to claim 1, wherein, If the electric energy meter to be replaced is a three-phase three-wire electric energy meter including three phase lines, the number of voltage test circuits on the joint terminal block involved is 2, which are CB phase voltage test circuit and AB phase voltage test circuit; If the electric energy meter to be replaced is a three-phase four-wire electric energy meter including three phase lines and one neutral line, the number of voltage test circuits on the joint terminal block involved is 3, which are AN voltage test circuit, BN voltage test circuit and CN voltage test circuit.

3. The method according to claim 2, wherein, When the electric energy meter to be replaced is a three-phase three-wire electric energy meter including three phase lines, the CB phase voltage test circuit takes C phase as the high-voltage phase and B phase as the low-voltage phase; the AB phase voltage test circuit takes A phase as the high-voltage phase and B phase as the low-voltage phase; When the electric energy meter to be replaced is a three-phase four-wire electric energy meter including three phase lines and one neutral line, the AN voltage test circuit takes A phase as the high-voltage phase and N as the low-voltage phase; the BN voltage test circuit takes B phase as the high-voltage phase and N as the low-voltage phase; the CN voltage test circuit takes C phase as the high-voltage phase and N as the low-voltage phase.

4. The method according to any one of claims 1-3, wherein, The current ratio of the first clamp current transformer and the second clamp current transformer in each pair of clamp current transformers used is the same, and the error is consistent.

5. The method according to any one of claims 1-3, wherein, The single-phase electric energy meter is a power electric energy standard meter.

6. An electric energy metering system for implementing the electric energy loss metering method during electric energy meter replacement according to any one of claims 1 to 5, characterized in that, The single-phase electric energy meter is a power electric energy standard meter. The first clamp-on current transformer is clamped to the current input line of the high-voltage phase in the corresponding voltage test loop of the joint terminal box, the second clamp-on current transformer is clamped to the current output line of the high-voltage phase in the corresponding voltage test loop of the joint terminal box, and the secondary output windings of the first clamp-on current transformer and the second clamp-on current transformer in each voltage test loop are reversely connected in parallel with opposite polarities. The voltage input end of the single-phase electric energy meter is connected to the input connection terminal of the high-voltage phase in the corresponding voltage test loop of the joint terminal box, the voltage output end of the single-phase electric energy meter is connected to the input connection terminal of the low-voltage phase in the corresponding voltage test loop of the joint terminal box, the current input end of the single-phase electric energy meter is connected to the first connection point of the secondary output windings of the corresponding first clamp-on current transformer and second clamp-on current transformer, and the current output end of the single-phase electric energy meter is connected to the second connection point of the secondary output windings of the corresponding first clamp-on current transformer and second clamp-on current transformer.

7. The electricity loss measurement system during electricity meter replacement according to claim 6, characterized by, The power consumption metering module is further connected with the single-phase electric energy meter. The power consumption metering module records the power consumption wh1 sensed by the single-phase electric energy meter during the stage of short-circuiting the secondary windings of the high-voltage current transformer connected to the single-phase electric energy meter by moving the current short-circuiting piece of the joint terminal box. The power consumption metering module records the power consumption wh2 sensed by the single-phase electric energy meter during the stage of removing the single-phase electric energy meter. The power consumption metering module records the power consumption wh3 sensed by the single-phase electric energy meter during the stage of connecting the new single-phase electric energy meter to the joint terminal box and connecting the new single-phase electric energy meter to the secondary windings of the high-voltage current transformer by moving the current short-circuiting piece of the joint terminal box. The power consumption metering module calculates the power loss wh during the replacement of the single-phase electric energy meter based on the formula wh= wh1+ wh2 +wh3.

8. The electricity loss measurement system during electricity meter replacement according to claim 6 or 7, characterized by, The current ratio of the first clamp-on current transformer to the second clamp-on current transformer in each clamp-on current transformer pair is the same, and the error is consistent.

9. The electricity loss measurement system during electricity meter replacement according to claim 6 or 7, characterized by, The single-phase electric energy meter is a power electric energy standard meter.

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