Method and system for metering electric quantity loss during replacement period of electric energy meter

Abstract

The invention discloses an electric quantity loss metering method and system during electric energy meter replacement, and the method comprises the steps: firstly determining the number of voltage test loops related to the electric quantity metering of a to-be-replaced electric energy meter, and configuring a split core type current transformer pair and a single-phase electric energy meter for each voltage test loop; clamping a split core type current transformer pair to a current input line and a current output line of a high-voltage phase in each voltage test loop, and connecting a single-phase electric energy meter to a secondary winding of the corresponding split core type current transformer; then, short-circuiting a secondary winding of a high-voltage current transformer connected with the electric energy meter to be replaced, and recording the electricity consumption wh1 on the single-phase electric energy meter at the stage; dismounting the electric energy meter to be replaced, and recording the electricity consumption wh2 on the single-phase electric energy meter at the stage; the new electric energy meter is connected to the combined junction box, and the electricity consumption wh3 of the single-phase electric energy meter at the stage is recorded; and finally, calculating the power loss during the replacement of the electric energy meter according to wh1, wh2 and wh3. The method is higher in efficiency and higher in safety.

Description

Technical Field

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

[0002] With the construction of the electricity spot market, power supply companies have begun to promote the application of flexible-rate electric energy meters. At present, power supply companies have only completed the replacement of electric energy meters for some large industrial users, and in the later stage, they will also promote the batch rotation of metering electric meters for all high-voltage users. During the replacement of the electric energy meter, since the old electric energy meter needs to be removed, there will be a period of non-metering state. After statistics, the duration of this state is generally more than 15 minutes. For small-power users, although there is electricity quantity loss during meter replacement, the electricity quantity is small and the impact is small. However, for high-voltage large-load users, the electricity quantity loss during meter replacement is more than 10,000 kWh, and there will be a large amount of error electricity quantity, and it will also be very difficult to coordinate the electricity refund and compensation with customers. Taking a steel plant with double-loop power supply as an example, the load power of its two lines is about 80,000 kW, and the electricity quantity loss during meter replacement (calculated according to 15 minutes) is about 20,000 kWh.

[0003] At present, there are mainly the following difficulties in the refund and compensation of electricity quantity loss during the replacement of high-voltage metering devices: (1) It is difficult to obtain data in real time, and the calculation accuracy is relatively low. Conventional refund and compensation of electricity quantity generally requires professional and technical personnel to calculate after meter replacement. According to the requirements of the operation instruction manual for the installation and removal of metering devices, the electricity consumption during the non-metering period is roughly calculated by recording the instantaneous power before meter replacement and the time before and after meter replacement. Since the customer's power is changing in real time, the calculation accuracy of this solution is greatly affected by the load fluctuation. (2) On-site work depends on manual labor, and the automation level of equipment needs to be improved. At present, when metering personnel perform on-site meter replacement, the meter reading record sheet at the meter base and the electricity quantity loss refund and compensation form are mainly manually recorded, there is a risk of missing or mis-copying the meter reading at the meter base, and it needs to be repeatedly reviewed by a special person, with low work efficiency, high labor cost, and lack of automated meter base entry, electricity quantity loss recording and work order printing equipment.

[0004] Therefore, some researchers have studied the measurement of power loss. For example, the patent document with the application number 201611015234 discloses a method for replacing an electricity meter without power interruption by connecting a standard meter. In this method, a standard meter is connected to the electricity meter circuit. During the process of removing the old electricity meter and installing the new one, a power measurement circuit is built by switching the short-circuit piece in the power measurement device, and the power measurement during the meter replacement process is realized by using the standard meter. However, since the power measurement device usually has functions of anti-theft and anti-stealing electricity, 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, and there are no other exposed measurement points. Therefore, when connecting the standard meter to the junction box, the 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. Moreover, the space in the junction box is small, which limits the operating space and thus affects the meter replacement efficiency. In addition, insecure connection of the wiring terminals will also affect safety. Summary of the Invention

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

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for measuring power loss during electricity meter replacement is as follows: Determine the number of voltage test circuits on the combined junction box involved in the power measurement of the electricity meter to be replaced; Configure a pair of clamp-on current transformers and a single-phase electricity meter for each voltage test circuit, where the pair of clamp-on current transformers includes a first clamp-on current transformer and a second clamp-on current transformer; 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 combined 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 combined junction box, and reverse-parallel the secondary output windings of the first clamp-on current transformer and the second clamp-on current transformer corresponding to each voltage test circuit; Connect the voltage input terminal of the single-phase electricity meter to the input connection terminal of the high-voltage phase in the corresponding voltage test circuit on the combined junction box, connect the voltage output terminal of the single-phase electricity meter to the input connection terminal of the low-voltage phase in the corresponding voltage test circuit on the combined junction box, connect the current input terminal of the single-phase electricity meter 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 connect the current output terminal of the single-phase electricity meter to the second connection point of the secondary output windings of the corresponding first clamp-on current transformer and second clamp-on current transformer; Move the current short - circuit piece of the mobile combined junction box to short - circuit the secondary winding of the high - voltage current transformer connected to the electricity meter to be replaced, and record the power consumption wh1 sensed on the single - phase electricity meter at this time; Next, remove the electricity meter to be replaced, and record the power consumption wh2 sensed on the single - phase electricity meter at this time; Then, connect the new electricity meter to the combined junction box, move the current short - circuit piece of the combined junction box to connect the new electricity meter to the secondary winding of the high - voltage current transformer, complete the replacement of the electricity meter, and record the power consumption wh3 sensed on the single - phase electricity meter at this time; Finally, calculate the power loss wh during the electricity meter replacement, as shown in the following formula: wh = wh1+ wh2 +wh3.

[0007] Further, if the electricity meter to be replaced is a three - phase three - wire electricity meter including three phase lines, the number of voltage test circuits on the involved combined junction box is 2, namely the CB - phase voltage test circuit and the AB - phase voltage test circuit; If the electricity meter to be replaced is a three - phase four - wire electricity meter including three phase lines and one neutral line, the number of voltage test circuits on the involved combined junction box is 3, namely the AN voltage test circuit, the BN voltage test circuit and the CN voltage test circuit.

[0008] Further, when the electricity meter to be replaced is a three - phase three - wire electricity meter including three phase lines, in the CB - phase voltage test circuit, the C - phase is the high - voltage phase and the B - phase is the low - voltage phase; in the AB - phase voltage test circuit, the A - phase is the high - voltage phase and the B - phase is the low - voltage phase; When the electricity meter to be replaced is a three - phase four - wire electricity meter including three phase lines and one neutral line, in the AN voltage test circuit, the A - phase is the high - voltage phase and the N is the low - voltage phase; in the BN voltage test circuit, the B - phase is the high - voltage phase and the N is the low - voltage phase; in the CN voltage test circuit, the C - phase is the high - voltage phase and the N is the low - voltage phase.

[0009] Further, the first clamp - type current transformer and the second clamp - type current transformer in each pair of clamp - type current transformers used have the same current ratio and consistent error.

[0010] Further, the single - phase electricity meter used is a power energy standard meter.

[0011] An electricity meter replacement power loss measurement system for implementing the above - mentioned power loss measurement method during electricity meter replacement includes a pair of clamp - type current transformers and a single - phase electricity meter respectively configured for each voltage test circuit on the combined junction box involved in the power consumption measurement of the electricity meter to be replaced, where the pair of clamp - type current transformers includes a first clamp - type current transformer and a second clamp - type current transformer; Among them, the first clamp - type current transformer clamps onto the current input line of the high - voltage phase in the corresponding voltage test circuit loop on the combined wiring box, and the second clamp - type current transformer clamps onto the current output line of the high - voltage phase in the corresponding voltage test circuit loop on the combined wiring box. Moreover, the secondary output windings of the first and second clamp - type current transformers corresponding to each voltage test circuit are reversely connected in parallel. The voltage input terminal of the single - phase watt - hour meter is connected to the input connection terminal of the high - voltage phase in the corresponding voltage test circuit loop on the combined wiring box, the voltage output terminal of the single - phase watt - hour meter is connected to the input connection terminal of the low - voltage phase in the corresponding voltage test circuit loop on the combined wiring box, the current input terminal of the single - phase watt - hour meter is connected to the first connection point of the secondary output windings of the corresponding first and second clamp - type current transformers, and the current output terminal of the single - phase watt - hour meter is connected to the second connection point of the secondary output windings of the corresponding first and second clamp - type current transformers.

[0012] Furthermore, it also includes a power consumption measurement module, and the power consumption measurement module is connected to the single - phase watt - hour meter. The power consumption measurement module records the power consumption wh1 sensed by the single - phase watt - hour meter during the stage when the current short - circuit piece of the mobile combined wiring box shorts the secondary winding of the high - voltage current transformer connected to the watt - hour meter to be replaced. The power consumption measurement module records the power consumption wh2 sensed by the single - phase watt - hour meter during the stage of removing the watt - hour meter to be replaced. The power consumption measurement module records the power consumption wh3 sensed by the single - phase watt - hour meter during the stage when, after connecting the new watt - hour meter to the combined wiring box, the current short - circuit piece of the mobile combined wiring box is moved to connect the new watt - hour meter to the secondary winding of the high - voltage current transformer. And the power consumption measurement module calculates the power loss wh during the watt - hour meter replacement period based on the formula wh = wh1+ wh2 +wh3.

[0013] Furthermore, for each pair of clamp - type current transformers, the first and second clamp - type current transformers have the same current ratio and consistent errors.

[0014] Furthermore, the single - phase watt - hour meter is a power - energy standard meter. Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses clamp - type current transformers to clamp onto the current input line and current output line on the combined wiring box, and connects the secondary windings of the clamp - type current transformers to the watt - hour meter, realizing current detection, thereby measuring the power loss. The present invention has low requirements for the operation space, simple operation, and higher meter - changing efficiency. In addition, the connection of the clamp - type current transformers is relatively firm and not easy to fall off. Even if it falls off, it will not cause safety accidents. Description of the Drawings

[0015] Figure 1It is a schematic flow chart of the method for measuring power loss during the replacement of an electric energy meter provided by an embodiment of the present invention.

[0016] Figure 2 It is a schematic circuit diagram of the CB-phase voltage test circuit loop in the first case in the present invention.

[0017] Figure 3 It is a schematic circuit diagram of the CB-phase voltage test circuit loop in the second case in the present invention.

[0018] Figure 4 It is a schematic circuit diagram of the CB-phase voltage test circuit loop in the third case in the present invention.

[0019] Figure 5 It is a schematic circuit diagram of the CB-phase voltage test circuit loop in the fourth case in the present invention.

[0020] Figure 6 It is a schematic circuit diagram of the CB-phase voltage test circuit loop in the fifth case in the present invention. Detailed implementation manners

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] Embodiment 1 As Figure 1 shown, this embodiment provides a method for measuring power loss during the replacement of an electric energy meter, including the following steps: Step 1: Determine the number of voltage test circuit loops on the combined wiring box involved in the power 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 circuit loops is 2, namely the CB-phase voltage test circuit loop and the AB-phase voltage test circuit loop. If the electric energy meter to be replaced is a three-phase four-wire electric energy meter including three phase lines and a neutral line, the number of voltage test circuit loops is 3, namely the AN voltage test circuit loop, the BN voltage test circuit loop, and the CN voltage test circuit loop.

[0023] Configure a pair of clamp-on current transformers and a single-phase electric energy meter for each voltage test circuit loop, where the pair of clamp-on current transformers includes a first clamp-on current transformer and a second clamp-on current transformer, and the current ratios of the first clamp-on current transformer and the second clamp-on current transformer are the same and the errors are consistent. The single-phase electric energy meter is a power energy standard meter.

[0024] Step 2: For each pair of clamp-on current transformers, clamp the first clamp-on current transformer onto the current input line of the high-voltage phase in the corresponding voltage test circuit loop on the combined wiring box, and clamp the second clamp-on current transformer onto the current output line of the high-voltage phase in the corresponding voltage test circuit loop on the combined wiring box. Reverse-parallel connect the secondary output windings of the first and second clamp-on current transformers corresponding to each voltage test circuit loop.

[0025] When the electricity meter to be replaced is a three-phase three-wire electricity meter including three phase lines, in the CB phase voltage test circuit, phase C is the high-voltage phase and phase B is the low-voltage phase; in the AB phase voltage test circuit, phase A is the high-voltage phase and phase B is the low-voltage phase.

[0026] When the electricity meter to be replaced is a three-phase four-wire electricity meter including three phase lines and a neutral line, in the AN voltage test circuit, phase A is the high-voltage phase and N is the low-voltage phase; in the BN voltage test circuit, phase B is the high-voltage phase and N is the low-voltage phase; in the CN voltage test circuit, phase C is the high-voltage phase and N is the low-voltage phase.

[0027] Assume that the electricity meter to be replaced is a three-phase three-wire electricity meter. For the CB phase voltage test circuit, the connection method of its corresponding pair of clamp-on current transformers is as Figure 2 shown. In the CB phase voltage test circuit, the high-voltage phase is phase C and the low-voltage phase is phase B. Without power interruption to the user, the high-voltage current is converted into low-voltage current through the high-voltage current transformer, and the secondary current ic2 is output from the secondary winding of the high-voltage current transformer according to the current ratio and input to the electricity meter WH1 to be replaced through the combined wiring box JB. Clamp the first clamp-on current transformer TA1 onto the C-phase current input line on the combined wiring box JB, and clamp the second clamp-on current transformer TA2 onto the C-phase current output line on the combined wiring box JB. Reverse-parallel connect the secondary output windings of the first clamp-on current transformer TA1 and the second clamp-on current transformer TA2.

[0028] Step 3: Connect the voltage input terminal of the single-phase electricity meter to the input connection terminal of the high-voltage phase in the corresponding voltage test circuit loop on the combined wiring box, connect the voltage output terminal of the single-phase electricity meter to the input connection terminal of the low-voltage phase in the corresponding voltage test circuit loop on the combined wiring box, connect the current input terminal of the single-phase electricity meter to the first connection point of the secondary output windings of the corresponding first and second clamp-on current transformers, and connect the current output terminal of the single-phase electricity meter to the second connection point of the secondary output windings of the corresponding first and second clamp-on current transformers.

[0029] As Figure 2As shown in the figure, for the CB-phase voltage test circuit, connect the voltage input terminal of the single-phase watt-hour meter WH2 to the C-phase input connection terminal Uc on the combined wiring box JB, the voltage output terminal to the B-phase input connection terminal Ub on the combined wiring box JB, the current input terminal to the first connection point of the secondary output windings of the first clamp-on current transformer TA1 and the second clamp-on current transformer TA2, and the current output terminal to the second connection point of the secondary output windings of the first clamp-on current transformer TA1 and the second clamp-on current transformer TA2. The other AB-phase voltage test circuits are connected in the same way.

[0030] If the watt-hour meter to be replaced is a three-phase four-wire three-phase watt-hour meter, then connect the AN voltage test circuit, the BN voltage test circuit, and the CN voltage test circuit respectively in the manner described in Steps 2 and 3.

[0031] After the connection is completed, for the CB-phase voltage test circuit, at this time, the C-phase input current is equal to the C-phase output current. The two clamp-on current transformers measure the same current ic2. Due to the opposite polarities, the output current TA1_ic2 of TA1 and the output current TA2_ic2 of TA2 are equal in magnitude and opposite in direction. The sum of the two secondary currents on the single-phase watt-hour meter, the current ic0, is zero. At this time, the watt-hour meter WH1 to be replaced will continue to measure the electricity normally, and the measured electricity of WH2 is 0 at this time.

[0032] Step 4: Move the current shorting piece of the combined wiring box to short-circuit the secondary winding of the high-voltage current transformer connected to the watt-hour meter to be replaced, and record the electricity consumption wh1 sensed on the single-phase watt-hour meter at this stage.

[0033] As Figure 2 shown, when the actual user is using electricity, the high-voltage three-phase electricity (three wires U, V, and W) is at a high voltage. Through the high-voltage current transformer, the high-voltage electricity is converted into low-voltage electricity, and the secondary current ic2 is output and connected to the watt-hour meter WH1 through the combined wiring box JB and reaches the user's residence. In this embodiment, the secondary winding of the high-voltage current transformer is the winding on the user side, and the primary winding is the high-voltage side.

[0034] As Figure 3 shown, for the CB-phase voltage test circuit, at this time, 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 measure the shunt ic3 of the CT secondary current. Generally, ic3 is much smaller than ic2, and in most cases, it can be considered that ic3 is 0; at this time, the base value of the electricity consumption wh0 on WH1 can be recorded; the current on WH2 at this stage is ic0 = TA1_ic2 - TA2_ic3, and record the electricity consumption wh1 on WH2.

[0035] 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.

[0036] As Figure 4 shown, for the CB phase voltage test circuit, at this time, the first clamp-on current transformer TA1 measures all the CT secondary currents ic2, while the second clamp-on current transformer TA2 measures the current ic3 as zero, and the output current of TA2, TA2_ic3 = 0. At this stage, WH2 measures all the secondary currents of phase C, ic0 = TA1_ic2, and record the electricity consumption wh2 on WH2 at this stage.

[0037] Step 6: Connect the new electricity meter to the combined wiring box, and move the current short-circuit piece of the combined wiring box to connect the new electricity meter to the secondary winding of the high-voltage current transformer, complete the replacement of the electricity meter, and record the electricity consumption wh3 sensed by the single-phase electricity meter at this stage.

[0038] As Figure 5 shown, for the CB phase voltage test circuit, there is also a small amount of power loss when the new electricity meter WH3 is connected to the combined wiring box JB. Record the electricity consumption wh3 on WH2 at this stage. Move the current short-circuit piece of WH2, as Figure 6 shown, to connect the new electricity meter to the secondary winding of the high-voltage current transformer. All the secondary currents of the high-voltage current transformer pass through the new electricity meter WH3. At this time, since the output currents of TA1 and TA2 are superimposed to be 0, there is no electricity consumption on WH2 at this stage.

[0039] Step 7: Calculate the power loss during the electricity meter replacement wh = wh1 + wh2 + wh3, and at this time, update the reading of the new electricity meter WH3 to wh0 + wh.

[0040] Embodiment 2 The embodiment of the present invention provides an electricity meter replacement power loss measurement system for implementing the above-mentioned electricity meter replacement power loss measurement method, including a power consumption measurement module, and a pair of clamp-on current transformers and a single-phase electricity meter equal to the number of voltage test circuits on the combined wiring box related to the electricity meter measurement of the electricity meter to be replaced, that is, one pair of clamp-on current transformers and one single-phase electricity meter are configured for each voltage test circuit. Among them, each pair of clamp-on current transformers includes a first clamp-on current transformer and a second clamp-on current transformer.

[0041] In each pair of clamp-on current transformers, the first clamp-on current transformer clamps to the current input line of the high-voltage phase in the corresponding voltage test circuit on the combined wiring box, and the second clamp-on current transformer clamps to the current output line of the high-voltage phase in the corresponding voltage test circuit on the combined wiring box. The secondary output windings of the first clamp-on current transformer and the second clamp-on current transformer corresponding to each voltage test circuit are reversely connected in parallel.

[0042] The voltage input terminal of each single-phase watt-hour meter is connected to the input connection terminal of the high-voltage phase in the corresponding voltage test circuit loop on the combined wiring box, the voltage output terminal of each single-phase watt-hour meter is connected to the input connection terminal of the low-voltage phase in the corresponding voltage test circuit loop on the combined wiring box, the current input terminal of each single-phase watt-hour 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 terminal of each single-phase watt-hour 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.

[0043] The power consumption measurement module records the current short-circuit piece of the mobile combined wiring box to record the power consumption wh1 on the single-phase watt-hour meter during the stage when the secondary winding of the high-voltage current transformer connected to the watt-hour meter to be replaced is short-circuited, and records the power consumption wh2 on the single-phase watt-hour meter during the stage of removing the watt-hour meter to be replaced, and records the power consumption wh3 on the single-phase watt-hour meter during the stage of connecting the new watt-hour meter to the combined wiring box and moving the current short-circuit piece of the mobile combined wiring box to connect the new watt-hour meter to the secondary winding of the high-voltage current transformer.

[0044] Finally, the power loss calculation module calculates the power loss during the watt-hour meter replacement based on the formula wh = wh1 + wh2 + wh3.

[0045] Wherein, if the watt-hour meter to be replaced is a single-phase watt-hour meter including one phase wire and one neutral wire, the number of voltage test circuits of the watt-hour meter to be replaced is 1; if the watt-hour meter to be replaced is a three-phase three-wire watt-hour meter including three phase wires, the number of voltage test circuits of the watt-hour meter to be replaced is 2, namely the CB phase voltage test circuit and the AB phase voltage test circuit; if the watt-hour meter to be replaced is a three-phase four-wire watt-hour meter including three phase wires and one neutral wire, the number of voltage test circuits of the watt-hour meter to be replaced is 3, namely the AN voltage test circuit, the BN voltage test circuit and the CN voltage test circuit. In the CB phase voltage test circuit, the C phase is the high-voltage phase and the B phase is the low-voltage phase; in the AB phase voltage test circuit, the A phase is the high-voltage phase and the B phase is the low-voltage phase, in the AN voltage test circuit, the A phase is the high-voltage phase and the N is the low-voltage phase; in the BN voltage test circuit, the B phase is the high-voltage phase and the N is the low-voltage phase; in the CN voltage test circuit, the C phase is the high-voltage phase and the N is the low-voltage phase.

[0046] Wherein, the current ratios of the first clamp-on current transformer and the second clamp-on current transformer in each pair of clamp-on current transformers are the same and the errors are consistent. The single-phase watt-hour meter is a power energy standard meter.

[0047] It should be noted that in this embodiment, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0048] It should be understood that the above embodiments and the descriptions in the specification only illustrate the principles, main features and advantages of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the protection scope of the present invention.

Claims

1. A method for measuring power loss during the replacement of an electric energy meter, characterized in that: The process is as follows: Determine the number of voltage test circuits on the joint junction box involved in the electricity metering of the energy meter to be replaced; A clamp-on current transformer pair and a single-phase electric energy meter are configured for each voltage test circuit, wherein the clamp-on current transformer pair includes a first clamp-on current transformer and a second clamp-on current transformer; Clamp the first clamp-on current transformer to the current input line of the high-voltage phase in the corresponding voltage test circuit loop on the joint 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 joint junction box, and reversely connect the polarities of 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; 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 circuit loop on the joint junction 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 circuit loop on the joint junction box, connect the current input end of the single-phase electric energy meter to the first connection point of the corresponding first clamp-type current transformer and the second clamp-type current transformer secondary output winding, and connect the current output end of the single-phase electric energy meter to the second connection point of the corresponding first clamp-type current transformer and the second clamp-type current transformer secondary output winding; Move the current short-circuit piece of the joint junction box to short-circuit the secondary winding of the high-voltage current transformer connected to the electric energy meter to be replaced, and record the power consumption wh1 sensed on the single-phase electric energy meter at this time; Next, remove the energy meter to be replaced and record the power consumption wh2 sensed on the single-phase energy meter at this time; Then, connect the new energy meter to the joint junction box, move the current short-circuit piece of the joint junction box, connect the new energy meter to the secondary winding of the high-voltage current transformer, complete the energy meter replacement, and record the power consumption wh3 sensed on the single-phase energy meter at this time; Finally, the power loss wh during the energy meter replacement period is calculated as shown in the following formula: wh= wh1+ wh2 +wh3.

2. A method for measuring power loss during replacement of an electric energy meter according to claim 1, characterized in that: 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 junction box involved is 2, namely, the CB phase voltage test circuit and the 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 combined junction box involved is 3, namely, the AN voltage test circuit, the BN voltage test circuit and the CN voltage test circuit.

3. A method for measuring power loss during replacement of an electric energy meter according to claim 2, characterized in that: When the electric energy meter to be replaced is a three-phase three-wire electric energy meter including three phase lines, the C phase is the high voltage phase and the B phase is the low voltage phase in the CB phase voltage test circuit; the A phase is the high voltage phase and the B phase is the low voltage phase in the AB phase voltage test circuit; 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, phase A in the AN voltage test circuit is the high-voltage phase, and N is the low-voltage phase; phase B in the BN voltage test circuit is the high-voltage phase, and N is the low-voltage phase; phase C in the CN voltage test circuit is the high-voltage phase, and N is the low-voltage phase.

4. A method for measuring power loss during replacement of an electric energy meter according to any one of claims 1 to 3, characterized in that: The first clamp-on current transformer and the second clamp-on current transformer in each clamp-on current transformer pair used have the same current ratio and the same error.

5. A method for measuring power loss during replacement of an electric energy meter according to any one of claims 1 to 3, characterized in that: The single-phase electric energy meter used is a standard power and electric energy meter.

6. A system for measuring the power loss during the replacement of an electric energy meter, which implements the method for measuring the power loss during the replacement of an electric energy meter as claimed in any one of claims 1 to 5, characterized in that: It includes a clamp current transformer pair and a single-phase electric energy meter respectively configured for each voltage test circuit on a joint junction box involved in the electric energy metering to be replaced, wherein the clamp current transformer pair includes a first clamp current transformer and a second clamp current transformer; Wherein, the first clamp-type current transformer is clamped to the current input line of the high-voltage phase in the corresponding voltage test circuit loop on the joint junction box, and the second clamp-type current transformer is clamped to the current output line of the high-voltage phase in the corresponding voltage test circuit on the joint junction box, and the polarity of the secondary output windings of the first clamp-type current transformer and the second clamp-type current transformer corresponding to each voltage test circuit are reversely connected in parallel; 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 circuit loop on the combined junction 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 circuit loop on the combined junction box, the current input end of the single-phase electric energy meter is connected to the first connection point of the corresponding first clamp-on current transformer and the second clamp-on current transformer secondary output winding, and the current output end of the single-phase electric energy meter is connected to the second connection point of the corresponding first clamp-on current transformer and the second clamp-on current transformer secondary output winding.

7. The system for measuring power loss during replacement of electric energy meters according to claim 6, characterized in that: It also includes an electricity consumption metering module, which is connected to a single-phase electric energy meter; The power consumption metering module records the power consumption wh1 sensed by the single-phase power meter during the stage when the current short-circuit piece of the mobile joint junction box short-circuits the secondary winding of the high-voltage current transformer connected to the power meter to be replaced; The power consumption metering module records the power consumption wh2 sensed by the single-phase power meter during the stage of removing the power meter to be replaced; The power consumption metering module records the power consumption wh3 sensed by the single-phase power meter during the stage of connecting the new power meter to the joint junction box and moving the current short-circuit piece of the joint junction box to connect the new power meter to the secondary winding of the high-voltage current transformer; The power consumption metering module calculates the power loss wh during the replacement of the power meter based on the formula wh= wh1+ wh2 +wh3.

8. The system for measuring power loss during replacement of electric energy meters according to claim 6 or 7, characterized in that: The first clamp-on current transformer and the second clamp-on current transformer in each clamp-on current transformer pair have the same current ratio and the same error.

9. The system for measuring power loss during replacement of electric energy meters according to claim 6 or 7, characterized in that: The single-phase electric energy meter is a standard power and electric energy meter.

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