Online monitoring method and device for energy efficiency grade of power transformer

Abstract

The invention discloses an on-line monitoring method and system for the energy efficiency grade of a power transformer, and the method comprises the steps: enabling a wireless current sensor to be installed at the primary side of the transformer, and obtaining the amplitude and phase information of the three-phase current of the primary side of the transformer through the wireless current sensor; a measuring unit is installed on the secondary side of the transformer, and the amplitude and phase information of the voltage and current of the secondary side of the transformer are obtained through the measuring unit; the control analysis unit is used for monitoring no-load loss and load loss of the transformer according to the three-phase current amplitude and phase information of the primary side of the transformer, the voltage and current amplitude and phase information of the secondary side of the transformer and the parameter information of the transformer, comparing the monitoring values of the no-load loss and the load loss with the energy efficiency limit value of the transformer, and outputting the energy efficiency limit value of the transformer. And determining the energy efficiency grade of the transformer. Under the condition of no power failure, the energy efficiency level is monitored on line, and the defect that no-load loss of the transformer and the energy efficiency level cannot be monitored in a live-line mode is overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrical measurement, in particular to an online monitoring method and device for energy efficiency grade of power transformer. BACKGROUND

[0002] As an important electrical equipment in power system, the loss of power transformer is also an important part of system loss. Although the efficiency of transformer has reached more than 95%, but due to the fact that a considerable number of high energy consumption transformers are still running in the power grid in China, the transformer loss accounts for about 3% of the total power generation in the national power grid, and the loss of distribution transformer accounts for about 60%-80% of the entire distribution network loss. The improvement of transformer energy efficiency will greatly help energy saving and loss reduction. In the development process of energy saving technology of transformers in China, S7, S9, S11 and other series of replacement process have been experienced, and the limits of no-load loss and load loss have been continuously reduced. In order to determine whether the energy efficiency grade of transformer is false, it is necessary to actually measure the no-load loss and load loss of transformer. At present, no-load test and load test are generally carried out to measure the no-load loss and load loss of transformer respectively, and then compared with the limit value specified in GB 20052-2020 "Power Transformer Energy Efficiency Limit Value and Energy Efficiency Grade", so as to determine whether the energy efficiency grade of transformer is false. However, the no-load test and load test of transformer can only be carried out under offline conditions, and it is difficult to coordinate the power transformer outage time window after operation, and it is difficult to disconnect the line and cannot be moved. The test equipment is heavy and large in size, and it does not have the condition to carry out on-site test. With the extension of operation period, whether the energy efficiency level of transformer changes, and whether the measurement results of no-load test before operation are accurate, all have adverse effects on the improvement of energy efficiency level of power transformer. At present, there is an urgent need for a method which can realize online monitoring of energy efficiency grade of transformer to ensure that the energy efficiency level of transformer in operation meets the requirements of standard specification. SUMMARY

[0003] In view of the above technical problems, the present application provides an online monitoring method for energy efficiency grade of power transformer, comprising:

[0004] A wireless current sensor is installed on the primary side of the transformer, the three-phase current amplitude and phase information of the primary side of the transformer are obtained through the wireless current sensor, and the three-phase current amplitude and phase information of the primary side of the transformer are transmitted to the control analysis unit;

[0005] A measurement unit is installed on the secondary side of the transformer, the amplitude and phase information of voltage and current of the secondary side of the transformer are obtained through the measurement unit, and the amplitude and phase information of voltage and current of the secondary side of the transformer and the parameter information of the transformer are transmitted to the control analysis unit;

[0006] The control analysis unit monitors the no-load loss and load loss of the transformer according to the transformer primary side three-phase current amplitude and phase information, the transformer secondary side voltage, current amplitude and phase information, and the transformer parameter information, compares the monitoring values of the no-load loss and load loss with the energy efficiency limit value of the transformer, and determines the energy efficiency level of the transformer.

[0007] Further, the wireless current sensor adopts an open magnetic core structure, an internal power taking structure takes power through electromagnetic induction principle, and a battery is configured as a standby power supply.

[0008] Further, the measurement unit comprises a current transformer, a voltage transformer, a terminal device and a master station system.

[0009] The current transformer and the voltage transformer obtain the voltage and current of the transformer secondary side, and send the voltage and current to the terminal device in the measurement unit.

[0010] The terminal device obtains the voltage, current amplitude and phase information of the transformer secondary side, and sends the voltage, current amplitude and phase information of the transformer secondary side to the master station system in the measurement unit.

[0011] The master station system transmits the voltage, current amplitude and phase information of the transformer secondary side and the parameter information of the transformer to the control analysis unit.

[0012] Further, the parameter information of the transformer comprises transformer capacity, primary and secondary rated voltage, short-circuit impedance percentage, connection mode, no-load loss, load loss and core type.

[0013] Further, the functions of the control analysis unit further comprise sending instructions to the wireless current sensor and the master station to realize synchronous acquisition of transformer primary and secondary electrical measurement data information, and storing the acquired information and the transformer parameter information.

[0014] Further, according to the transformer primary side three-phase current amplitude and phase information, the transformer secondary side voltage, current amplitude and phase information, and the transformer parameter information, the no-load loss and load loss of the transformer are monitored, and the specific calculation formula is as follows:

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] P 损 = P A + P B + P C

[0022] wherein: P 单相 is the single-phase active loss of the transformer, P 损 , P A , P B , P C are the total active loss of the transformer, the active loss of each phase A, B, C, respectively;

[0023] S N , I 1N , I 2N , U 2N are the rated capacity of the transformer, the rated line current at the high-voltage side, the rated line current at the low-voltage side, the rated line voltage at the low-voltage side, respectively, U k % is the short-circuit impedance voltage percentage of the transformer, U2、 are the line voltage and phase angle at the low-voltage side, respectively, I1, I2、 are the line current and phase angle at the high-voltage and low-voltage sides, respectively,

[0024] The secondary current obtained by the secondary-side measurement unit of the transformer is screened and the group of 5% rated current values is removed, and the remaining current data is [I 2(1) I 2(2) … I 2(n) ], the corresponding load rate [k (1) k (2) … k (n) ] can be calculated, and according to the transformer loss calculation formula:

[0025] P 损 = P0+k 2 P k

[0026] The least square method can be used to carry out linear regression on [P (1) P (2) … P (n) ] and [k (1) k (2) … k (n) ], and the variable coefficient and constant are the load loss P k and the no-load loss P0 of the transformer, respectively.

[0027] [P (1) P (2) … P (n)The active loss of the transformer.

[0028] The application also provides an online monitoring device for the energy efficiency grade of a power transformer, comprising a wireless current sensor, a measurement unit and a control analysis unit.

[0029] The wireless current sensor is installed on the primary side of the transformer and is used to acquire the amplitude and phase information of the three-phase current on the primary side of the transformer.

[0030] The measurement unit is installed on the secondary side of the transformer and is used to acquire the amplitude and phase information of the voltage and current on the secondary side of the transformer.

[0031] The analysis unit is used to receive the amplitude and phase information of the three-phase current on the primary side of the transformer transmitted by the wireless current sensor, the amplitude and phase information of the voltage and current on the secondary side of the transformer transmitted by the measurement unit, and the parameter information of the transformer, and to monitor the no-load loss and load loss of the transformer according to the amplitude and phase information of the three-phase current on the primary side of the transformer, the amplitude and phase information of the voltage and current on the secondary side of the transformer, and the parameter information of the transformer, compare the monitoring values of the no-load loss and load loss with the energy efficiency limit value of the transformer, and determine the energy efficiency grade of the transformer.

[0032] Further, the wireless current sensor adopts an open magnetic core structure, and an internal power taking structure takes power through electromagnetic induction principle and is configured with a battery as a backup power supply.

[0033] Further, the measurement unit comprises a current transformer, a voltage transformer, a terminal device and a master station system.

[0034] The current transformer and the voltage transformer acquire the voltage and current on the secondary side of the transformer and send the voltage and current to the terminal device in the measurement unit.

[0035] The terminal device acquires the amplitude and phase information of the voltage and current on the secondary side of the transformer and sends the amplitude and phase information of the voltage and current on the secondary side of the transformer to the master station system in the measurement unit.

[0036] The master station system transmits the amplitude and phase information of the voltage and current on the secondary side of the transformer and the parameter information of the transformer to the control analysis unit.

[0037] Further, the functions of the control analysis unit also include sending instructions to the wireless current sensor and the master station to realize the synchronous acquisition of the primary and secondary electrical measurement data information of the transformer, and storing the acquired information and the parameter information of the transformer.

[0038] The present application provides an online monitoring method and device for power transformer energy efficiency level, based on the principle relationship between transformer active operation loss and no-load loss, through monitoring transformer primary and secondary operation electrical information, completing online monitoring of no-load loss, further realizing online monitoring of energy efficiency level, solving the drawbacks that transformer no-load loss and energy efficiency level cannot be monitored under power. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a flowchart of an online monitoring method for power transformer energy efficiency level provided by an embodiment of the present application;

[0040] Figure 2 is a structural diagram of an online monitoring device for power transformer energy efficiency level provided by an embodiment of the present application. DETAILED DESCRIPTION

[0041] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a variety of ways beyond the specific embodiments described herein without departing from the scope of the present application, and it is understood that similar implementations can be made without departing from the scope of the present application, and therefore the present application is not limited to the specific implementations disclosed below.

[0042] Embodiment 1

[0043] As shown in Figure 1 , the present application provides an online monitoring method for power transformer energy efficiency level, which aims to realize online precise measurement of power transformer no-load loss and online monitoring of energy efficiency level under no power-off condition, the method comprising the following steps:

[0044] Step S101, a wireless current sensor is installed on the primary side of the transformer, the three-phase current amplitude and phase information of the primary side of the transformer are obtained through the wireless current sensor, and the three-phase current amplitude and phase information of the primary side of the transformer are sent to a control analysis unit.

[0045] The wireless current sensor is installed on the three-phase outgoing line of the primary side of the transformer, which can measure the three-phase current amplitude and phase information of the primary side, and communicate with the control analysis unit through Bluetooth, 4G / 5G, etc. Since it does not need to bear the ground insulation voltage, the insulation requirement is easy to meet, and the volume and weight can be greatly reduced. The wireless current sensor adopts an open magnetic core structure, the internal energy taking structure takes energy through electromagnetic induction principle, as the main source of electric energy, and a battery is configured as a backup power supply, which can realize live installation and removal.

[0046] Step S102, install the measurement unit on the secondary side of the transformer, obtain the amplitude and phase information of the voltage and current on the secondary side of the transformer through the measurement unit, and transmit the amplitude and phase information of the voltage and current on the secondary side of the transformer and the parameter information of the transformer to the control analysis unit.

[0047] The measurement unit comprises a current transformer, a voltage transformer, a terminal device and a master station system.

[0048] The current transformer and the voltage transformer obtain the voltage and current on the secondary side of the transformer and send them to the terminal device in the measurement unit; the current transformer and the voltage transformer are generally configured when the transformer is installed (if the secondary side voltage is 380V, no secondary side voltage transformer is needed), and convert the high voltage and large current on the secondary side of the transformer into low voltage and small current in proportion to the terminal device.

[0049] The terminal device obtains the amplitude and phase information of the voltage and current on the secondary side of the transformer and sends them to the master station system in the measurement unit.

[0050] The master station system communicates with the control analysis unit and transmits the amplitude and phase information of the voltage and current on the secondary side of the transformer and the parameter information of the transformer to the control analysis unit.

[0051] The parameter information of the transformer is marked on the nameplate, and the parameter information of the transformer includes the transformer capacity, primary and secondary rated voltage, short-circuit impedance percentage, wiring mode, no-load loss, load loss, core type and other data.

[0052] Step S102, the control analysis unit, according to the amplitude and phase information of the three-phase current on the primary side of the transformer, the amplitude and phase information of the voltage and current on the secondary side of the transformer, and the parameter information of the transformer, monitors the no-load loss and load loss of the transformer, compares the monitoring values of the no-load loss and load loss with the energy efficiency limit value of the transformer, and determines the energy efficiency grade of the transformer.

[0053] The main functions of the control analysis unit include two parts: one is to send instructions to the wireless current sensor and the master station to realize synchronous acquisition of the primary and secondary electrical measurement data information of the transformer, and to store the acquired information and the parameter information of the transformer; the other is to develop transformer no-load loss and load loss monitoring based on the foregoing stored information, and to compare the transformer parameters with the energy efficiency limit value specified in GB20052-2020 to determine the real energy efficiency grade of the transformer.

[0054] The calculation process of the energy efficiency grade monitoring algorithm includes several steps:

[0055] (1) Based on the real-time data of primary current, secondary current, secondary voltage amplitude and phase, combined with the transformer nameplate data, the transformer loss is calculated. This method only needs to install wireless current sensor on the transformer under voltage, without power outage operation and transformer primary voltage monitoring device. The calculation formula is as follows:

[0056]

[0057]

[0058]

[0059]

[0060] P 损 = P A + P B + P C (6)

[0061] Where: P 单相 is the single-phase active power loss of the transformer, P 损 , P A , P B , P C are the total active power loss of the transformer, A, B, C phase active power loss respectively;

[0062] S N , I 1N , I 2N , U 2N are the rated capacity of the transformer, the rated line current of the high voltage side, the rated line current of the low voltage side, the rated line voltage of the low voltage side respectively, U k % is the short-circuit impedance voltage percentage of the transformer, which is obtained from the transformer archive nameplate information, U1、 are the high voltage side line voltage and phase angle respectively;

[0063] U2、 are the low voltage side line voltage and phase angle respectively, I1、I2、 are the high, low voltage side line current and phase angle respectively, I1and are obtained by wireless current sensor, U2、 I2、 are obtained by secondary measurement unit.

[0064] (2) The secondary current obtained by the secondary side measurement unit of the transformer is screened and removed, and the remaining current data is [I 2(1) I 2(2) … I 2(n) ], which can be calculated to obtain the corresponding load rate [k (1) k (2)… k (n) The active power loss of the transformer has been obtained from step (1), and is [P]. (1) P (2) … P (n) According to the transformer loss calculation formula:

[0065] P 损 =P0+k 2 P k (7)

[0066] The least squares method can be used to [P] (1) P (2) … P (n) ] and [k (1) k (2) … k (n) A linear regression was performed, and the variable coefficients and constants were respectively the transformer load loss P. k And no-load loss P0.

[0067] (3) Based on the voltage level, rated capacity, wiring method, and core material type of the monitored transformer, find the upper limits of no-load loss and load loss corresponding to Level 1, Level 2, and Level 3 energy efficiency in GB 20052-2020, and adjust the transformer load loss P in step (2). k By comparing the no-load loss P0 with the search data, the energy efficiency level of the monitored transformer can be determined, thus realizing online monitoring of the transformer's energy efficiency level.

[0068] Example 2

[0069] like Figure 2 As shown, the present invention also provides an online monitoring device for the energy efficiency level of power transformers, comprising: a wireless current sensor, a measurement unit, and a control and analysis unit;

[0070] A wireless current sensor is installed on the primary side of the transformer to acquire the amplitude and phase information of the three-phase current on the primary side of the transformer.

[0071] The measuring unit is installed on the secondary side of the transformer to acquire the amplitude and phase information of the voltage and current on the secondary side of the transformer.

[0072] The analysis unit is used for receiving the transformer primary side three-phase current amplitude and phase information transmitted by the wireless current sensor, the voltage, current amplitude and phase information of the transformer secondary side transmitted by the measurement unit, and the parameter information of the transformer, and monitoring the no-load loss and load loss of the transformer according to the transformer primary side three-phase current amplitude and phase information, the voltage, current amplitude and phase information of the transformer secondary side, and the parameter information of the transformer, comparing the monitoring values of the no-load loss and load loss with the energy efficiency limit value of the transformer, and determining the energy efficiency grade of the transformer.

[0073] The wireless current sensor adopts an open magnetic core structure, an internal power taking structure takes power through electromagnetic induction principle, and a battery is configured as a standby power supply.

[0074] The measurement unit comprises a current transformer, a voltage transformer, a terminal device and a master station system.

[0075] The current transformer and the voltage transformer obtain the voltage and current of the transformer secondary side and send the voltage and current into the terminal device in the measurement unit.

[0076] The terminal device obtains the voltage, current amplitude and phase information of the transformer secondary side and sends the voltage, current amplitude and phase information of the transformer secondary side into the master station system in the measurement unit.

[0077] The master station system transmits the voltage, current amplitude and phase information of the transformer secondary side and the parameter information of the transformer to the control analysis unit.

[0078] The function of the control analysis unit further comprises sending instructions to the wireless current sensor and the master station, realizing synchronous acquisition of the transformer primary and secondary electrical measurement data information, and storing the acquired information and the parameter information of the transformer.

[0079] The application provides an online monitoring method and device for energy efficiency grade of a power transformer.

[0080] Those skilled in the art will appreciate that embodiments of the application can be devised for a method, a system, or a computer program product. Accordingly, the present application can be embodied in the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0081] The present application is described in reference to the flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 means for performing each of the one or more functions specified in the flowchart illustrations and / or block diagrams.

[0082] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 means for performing each of the one or more functions specified in the flowchart illustrations and / or block diagrams.

[0083] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 means for performing each of the one or more functions specified in the flowchart illustrations and / or block diagrams.

[0084] Finally, it should be noted that the above-mentioned embodiments are merely intended for describing the technical solutions of the present application, but not for limiting it. Although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the scope of claims of the present application.

Claims

1. An online monitoring method for the energy efficiency rating of power transformers, characterized in that, include: A wireless current sensor is installed on the primary side of the transformer to acquire the amplitude and phase information of the three-phase current on the primary side of the transformer; and the amplitude and phase information of the three-phase current on the primary side of the transformer is sent to the control and analysis unit. The measuring unit is installed on the secondary side of the transformer. The amplitude and phase information of the voltage and current on the secondary side of the transformer are obtained through the measuring unit. The amplitude and phase information of the voltage and current on the secondary side of the transformer, as well as the parameter information of the transformer, are transmitted to the control and analysis unit. The control and analysis unit monitors the no-load loss and load loss of the transformer based on the amplitude and phase information of the three-phase current on the primary side of the transformer, the amplitude and phase information of the voltage and current on the secondary side of the transformer, and the parameter information of the transformer. The monitored values ​​of no-load loss and load loss are compared with the energy efficiency limit value of the transformer to determine the energy efficiency level of the transformer.

2. The method according to claim 1, characterized in that, The wireless current sensor adopts an open magnetic core structure, and its internal energy harvesting structure harvests energy through the principle of electromagnetic induction. It is also equipped with a battery as a backup power source.

3. The method according to claim 1, characterized in that, The measurement unit includes: current transformers, voltage transformers, terminal equipment, and a master station system; The current transformer and voltage transformer acquire the voltage and current on the secondary side of the transformer and send the voltage and current to the terminal equipment in the measurement unit; The terminal device acquires the voltage, current amplitude, and phase information of the secondary side of the transformer and sends the voltage, current amplitude, and phase information of the secondary side of the transformer to the master station system in the measurement unit; The master station system transmits the voltage, current amplitude and phase information of the secondary side of the transformer, as well as the transformer's parameter information, to the control and analysis unit.

4. The method according to claim 1, characterized in that, The transformer's parameters include: transformer capacity, primary and secondary rated voltages, short-circuit impedance percentage, connection method, no-load loss, load loss, and core type.

5. The method according to claim 1, characterized in that, The functions of the control and analysis unit also include: sending commands to the wireless current sensor and the master station to realize the synchronous acquisition of primary and secondary electrical measurement data of the transformer, and storing the acquired information and transformer parameter information.

6. The method according to claim 1, characterized in that, Based on the amplitude and phase information of the three-phase current on the primary side of the transformer, the amplitude and phase information of the voltage and current on the secondary side of the transformer, and the transformer parameter information, the no-load loss and load loss of the transformer are monitored. The specific calculation formula is as follows: P 损 =P A +P B +P C Where: P 单相 For the single-phase active power loss of the transformer, P 损 P A P B P C These are the total active power loss of the transformer and the active power loss of each phase (A, B, and C), respectively. S N I 1N I 2N U 2N These are the transformer's rated capacity, rated line current on the high-voltage side, rated line current on the low-voltage side, and rated line voltage on the low-voltage side, respectively. k % represents the percentage of transformer short-circuit impedance voltage, U2, These represent the low-voltage side line voltage and phase angle, I1, I2, These are the high-voltage and low-voltage side line currents and phase angles, respectively. The secondary current obtained from the transformer secondary side measurement unit is filtered out, and groups with a value less than 5% of the rated current are removed. The remaining current data is [I 2(1) I 2(2) … I 2(n) The corresponding load factor [k] can be calculated. (1) k (2) … k (n) According to the transformer loss calculation formula: P 损 =P0+k 2 P k The least squares method can be used to [P] (1) P (2) … P (n) ] and [k (1) k (2) … k (n) A linear regression was performed, with the variable coefficients and constants being the transformer load loss P. k With no-load loss P0; [P (1) P (2) … P (n) [This refers to the active power loss of the transformer.] 7. An online monitoring device for the energy efficiency rating of power transformers, characterized in that, include: Wireless current sensor, measurement unit, and control and analysis unit; A wireless current sensor is installed on the primary side of the transformer to acquire the amplitude and phase information of the three-phase current on the primary side of the transformer. The measuring unit is installed on the secondary side of the transformer to acquire the amplitude and phase information of the voltage and current on the secondary side of the transformer. The analysis unit receives the amplitude and phase information of the three-phase current on the primary side of the transformer transmitted by the wireless current sensor, the voltage, current amplitude and phase information on the secondary side of the transformer transmitted by the measurement unit, and the transformer parameter information; and monitors the no-load loss and load loss of the transformer based on the amplitude and phase information of the three-phase current on the primary side of the transformer, the voltage, current amplitude and phase information on the secondary side of the transformer, and the transformer parameter information, and compares the monitored values ​​of no-load loss and load loss with the energy efficiency limit value of the transformer to determine the energy efficiency level of the transformer.

8. The apparatus according to claim 7, characterized in that, The wireless current sensor adopts an open magnetic core structure, and its internal energy harvesting structure harvests energy through the principle of electromagnetic induction. It is also equipped with a battery as a backup power source.

9. The apparatus according to claim 8, characterized in that, The measurement unit includes: current transformers, voltage transformers, terminal equipment, and a master station system; The current transformer and voltage transformer acquire the voltage and current on the secondary side of the transformer and send the voltage and current to the terminal equipment in the measurement unit; The terminal device acquires the voltage, current amplitude, and phase information of the secondary side of the transformer and sends this information to the master station system in the measurement unit. The master station system transmits the voltage, current amplitude and phase information of the secondary side of the transformer, as well as the transformer's parameter information, to the control and analysis unit.

10. The apparatus according to claim 8, characterized in that, The functions of the control and analysis unit also include: sending commands to the wireless current sensor and the master station to realize the synchronous acquisition of primary and secondary electrical measurement data of the transformer, and storing the acquired information and transformer parameter information.

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