A busbar cabinet capable of automatically measuring the capacitive current of a power distribution network and a measuring method

Abstract

The application discloses a busbar cabinet capable of automatically measuring the capacitive current of a power distribution network and a measuring method, which comprises a cabinet body and a measuring device, wherein the measuring device comprises a voltage transformer, a monitoring host, an automatic switch regulating device, a capacitive current tester and a grounding switch. The neutral point of the high-voltage winding of the voltage transformer is grounded through the grounding switch, and the output end of the capacitive current tester is connected with the secondary winding of the voltage transformer. The automatic switch regulating device is connected with the grounding switch. The monitoring host is connected with the capacitive current tester and the automatic switch regulating device respectively. In the application, the grounding switch is connected with the neutral point of the high-voltage winding of the voltage transformer connected with the bus, the capacitive current is measured on the secondary side of the voltage transformer through the capacitive current tester, and complicated switching operation is not needed, the grounding switch is controlled and the measuring data are acquired through a remote monitoring platform, the working difficulty is reduced, and the convenience and safety of operation are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronics, in particular to a busbar cabinet capable of automatically measuring the capacitance current of a power distribution network and a measuring method. BACKGROUND

[0002] During operation, ungrounded power systems inevitably have single-phase-to-ground faults. When a single-phase-to-ground fault occurs, if the capacitance current of the system is greater than 10 A, the arc generated thereby may not self-extinguish, and thus easily develops into a phase-to-phase short circuit fault. When the single-phase-to-ground is intermittent arc grounding, high-amplitude arc overvoltage is caused, and the equipment with weak insulation in the 10 kV system is easily broken down, causing serious accidents. Therefore, power grid operation and maintenance units must regularly test the capacitance current of each subsystem.

[0003] During the test, the operator needs to perform switching operations on the 10 kV busbar cabinet. After the busbar voltage transformer in the cabinet is switched from the operating state to the maintenance state, the arc eliminator on the neutral point of the busbar voltage transformer is short-circuited, the neutral point of the busbar voltage transformer is placed in a direct grounding state, and then the busbar voltage transformer is switched into the operating state. Finally, a non-power frequency measurement signal is injected at the secondary opening of the busbar voltage transformer, and the capacitance current of the busbar system is calculated through the feedback of the non-power frequency measurement signal. After the measurement is completed, the operator needs to switch the voltage transformer of the busbar cabinet to the maintenance state, restore the original connection of the neutral point, and then switch the voltage transformer of the busbar cabinet to the operating state.

[0004] It can be seen that the existing measurement process requires four switching operations on the voltage transformer of the measurement point busbar cabinet, and also requires wiring activities on the neutral point of the busbar cabinet voltage transformer. The entire process is not only cumbersome but also has safety hazards. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a busbar cabinet capable of automatically measuring the capacitance current of a power distribution network and a measuring method, which can simplify the operation steps of the capacitance current test of the busbar cabinet voltage transformer and improve the convenience and safety of the operation.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0007] A busbar cabinet capable of automatically measuring the capacitance current of a power distribution network, comprising a cabinet body and a measuring device located in the cabinet body, the measuring device comprising a voltage transformer, a monitoring host, an automatic switch adjustment device, a capacitance current tester and a grounding switch.

[0008] The neutral point of the high-voltage winding of the voltage transformer is grounded through the grounding knife switch, and the output end of the capacitance current tester is connected with the secondary winding of the voltage transformer.

[0009] The knife switch automatic adjusting device is connected with the grounding knife switch.

[0010] The monitoring host is connected with the capacitance current tester and the knife switch automatic adjusting device respectively, and is used for communicating with a remote monitoring platform.

[0011] The input end of the voltage transformer T1 is used for external connection of a bus.

[0012] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0013] A measurement method of a bus cabinet capable of automatically measuring capacitance current of a power distribution network, applied to the bus cabinet capable of automatically measuring capacitance current of the power distribution network, comprising the following steps:

[0014] S1, receiving and executing a knife switch closing instruction of a remote monitoring platform, and closing a grounding knife switch;

[0015] S2, measuring capacitance current of a voltage transformer through a capacitance current tester, and reporting a measurement result to the remote monitoring platform;

[0016] S3, receiving and executing a knife switch opening instruction of the remote monitoring platform, and opening the grounding knife switch.

[0017] The present application has the advantages that a bus cabinet and a measurement method capable of automatically measuring capacitance current of a power distribution network are provided, a grounding knife switch is connected to the neutral point of the high-voltage winding of the voltage transformer connected to the bus, when capacitance current is tested, the grounding knife switch can be closed through a knife switch automatic adjusting device, capacitance current can be directly measured on the secondary side of the voltage transformer through the capacitance current tester, without complicated switching operation, without rewiring, and the grounding knife switch and the measurement data can be automatically controlled and obtained through a remote monitoring platform, so that the operation steps of the voltage transformer capacitance current test of the bus cabinet are simplified, the work difficulty of the operator is reduced, the work efficiency is improved, and the convenience and safety of the work are improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A front view of a bus cabinet capable of automatically measuring capacitance current of a power distribution network according to an embodiment of the present application;

[0019] Figure 2 An internal connection diagram of a bus cabinet capable of automatically measuring capacitance current of a power distribution network according to an embodiment of the present application;

[0020] Figure 3A circuit connection schematic diagram of a grounding blade part of a busbar cabinet capable of automatically measuring a capacitive current of a power distribution network is related to an embodiment of the present application.

[0021] Figure 4 A measurement principle schematic diagram of a busbar cabinet capable of automatically measuring a capacitive current of a power distribution network is related to an embodiment of the present application.

[0022] Figure 5 A system block diagram of a busbar cabinet capable of automatically measuring a capacitive current of a power distribution network is related to an embodiment of the present application.

[0023] Figure 6 A step schematic diagram of a measurement method of a busbar cabinet capable of automatically measuring a capacitive current of a power distribution network is related to an embodiment of the present application.

[0024] Label explanation:

[0025] 1, cabinet body; 2, capacitive current tester; 3, rotating shaft; 4, operation hole; 5, first chamber; 6, second chamber; 7, third chamber; 8, display screen; 9, button; 10, monitoring host; 11, adjusting motor; 12, remote monitoring platform;

[0026] B1, arrester;

[0027] F1, high-voltage fuse;

[0028] G1, discharge gap;

[0029] J1, relay;

[0030] K1, grounding blade;

[0031] Q1, isolation handcart;

[0032] R1, harmonic eliminator;

[0033] T1, voltage transformer;

[0034] U1, control module. DETAILED DESCRIPTION

[0035] To explain the technical content, the purpose and the effect of the present application in detail, the following will be explained in combination with the embodiments and the drawings.

[0036] Please refer to Figures 1 to 5 A busbar cabinet capable of automatically measuring a capacitive current of a power distribution network, comprising a cabinet body 1 and a measurement device, the measurement device comprising a voltage transformer T1, a monitoring host 10, a blade automatic adjusting device, a capacitive current tester 2 and a grounding blade K1.

[0037] The neutral point of the high-voltage winding of the voltage transformer T1 is grounded through the grounding knife switch K1, and the output end of the capacitive current tester 2 is connected with the secondary winding of the voltage transformer T1.

[0038] The knife switch automatic adjusting device is connected with the grounding knife switch K1.

[0039] The monitoring host 10 is connected with the capacitive current tester 2 and the knife switch automatic adjusting device respectively, and is used for communicating with the remote monitoring platform 12.

[0040] The input end of the voltage transformer T1 is used for external connection of a bus.

[0041] From the above description, the beneficial effects of the present application are that: the grounding knife switch K1 is connected to the neutral point of the high-voltage winding of the voltage transformer T1 connected with the bus, when the capacitive current test is carried out, the grounding knife switch K1 is closed through the knife switch automatic adjusting device, and the capacitive current is directly measured on the secondary side of the voltage transformer T1 through the capacitive current tester 2, without complicated switching operation and without rewiring, and the grounding knife switch K1 and the measured data can be automatically controlled and obtained remotely through the remote monitoring platform 12, so that the operation steps of the capacitive current test of the bus cabinet voltage transformer T1 are simplified, the working difficulty of the operator is reduced, the operation efficiency is improved, and the convenience and safety of the operation are improved.

[0042] Further, the knife switch automatic adjusting device comprises an adjusting motor 11, a rotating shaft 3 and an operation hole 4 located on the cabinet body.

[0043] The rotating shaft 3 is rotatably arranged in the cabinet body at a position corresponding to the operation hole 4, and is fixedly connected with the moving contact of the grounding knife switch K1.

[0044] When the rotating shaft 3 rotates, the moving contact of the grounding knife switch K1 is brought into contact or separation with the static contact.

[0045] From the above description, the rotating shaft 3 is arranged in the cabinet body 1, the rotating shaft 3 is rotated by controlling the adjusting motor 11, and then the on-off state of the grounding knife switch K1 is switched, which has simple structure and is convenient to use.

[0046] Further, the measuring device further comprises a discharge gap G1.

[0047] One end of the discharge gap G1 is connected with the neutral point of the high-voltage winding of the voltage transformer T1, and the other end is grounded.

[0048] From the above description, the neutral point of the voltage transformer T1 is grounded through the discharge gap G1, and the discharge gap G1 is broken down when the voltage rises, so as to pull the potential to zero potential, thereby playing a protection role.

[0049] Further, the measuring device further comprises a harmonic eliminator R1;

[0050] The neutral point is grounded through the harmonic eliminator R1.

[0051] As can be seen from the above description, the neutral point is grounded through the harmonic eliminator R1, which can effectively prevent the ferroresonance overvoltage caused by the over-saturation of the voltage transformer T1, thereby increasing the stability of the circuit.

[0052] Further, the measuring device further comprises a relay J1;

[0053] The opening of the voltage transformer T1 is externally connected to a load through the relay J1.

[0054] As can be seen from the above description, the relay J1 is arranged at the input end of the voltage transformer T1, which can be temporarily disconnected from other loads during the capacitive current test, thereby improving the accuracy of the measurement.

[0055] Further, the capacitive current tester 2 comprises a control module U1, a display screen 8 and a button 9;

[0056] The output end of the control module U1 is connected to the secondary winding of the voltage transformer T1;

[0057] The control module U1 is connected to the monitoring host 10, the display screen 8 and the button 9.

[0058] As can be seen from the above description, the capacitive current tester 2 comprises a control module U1, a display screen 8 and a button 9. The display screen 8 can display the measurement results and other related data, which is convenient for the operator to understand in real time. Different buttons 9 can correspond to different functions, which is convenient for the operator to manually control, and is convenient and intelligent to use.

[0059] Please refer to Figures 4 to 6 A measurement method of a busbar cabinet capable of automatically measuring the capacitive current of a power distribution network, applied to the above-mentioned busbar cabinet capable of automatically measuring the capacitive current of the power distribution network, comprising the following steps:

[0060] S1, receiving and executing the disconnection instruction of the grounding knife switch K1 of the remote monitoring platform 12, and disconnecting the grounding knife switch K1;

[0061] S2, measuring the capacitive current of the voltage transformer T1 by the capacitive current tester 2, and reporting the measurement results to the remote monitoring platform 12;

[0062] S3, receiving and executing the closing instruction of the grounding knife switch K1 of the remote monitoring platform 12, and closing the grounding knife switch K1.

[0063] From the above description, the beneficial effects of the application are that: the ground knife switch K1 is connected to the neutral point of the high-voltage winding of the voltage transformer T1 of the bus, when the capacitance current test is performed, the ground knife switch K1 is closed, and the capacitance current is directly measured on the secondary side of the voltage transformer T1 through the capacitance current tester 2, without complicated switching operation and without rewiring, and the ground knife switch K1 and the measurement data can be automatically controlled and obtained through the remote monitoring platform 12, thereby simplifying the operation steps of the bus cabinet voltage transformer capacitance current test, reducing the work difficulty of the operator, improving the work efficiency, and improving the convenience and safety of the work.

[0064] Further, the disconnected ground knife switch K1 is specifically:

[0065] The control adjustment motor 11 drives the rotating shaft 3 to rotate, so that the moving contact and the static contact of the ground knife switch K1 are separated.

[0066] From the above description, the rotating shaft 3 is rotated by controlling the adjustment motor 11, and then the switching state of the ground knife switch K1 is switched, which has a simple structure and is convenient to use.

[0067] Further, the step S2 is specifically:

[0068] S21, a non-power frequency low-voltage signal is injected into the secondary winding of the voltage transformer T1;

[0069] S22, receiving a feedback signal corresponding to the non-power frequency low-voltage signal at the secondary winding of the voltage transformer T1;

[0070] S23, obtaining the capacitance current according to the feedback signal.

[0071] From the above description, the secondary winding of the voltage transformer T1 and the ground knife switch K1 are used to cooperate to measure the capacitance current, which reduces the switching operation amount and improves the work efficiency.

[0072] Further, the step S2 further includes:

[0073] Disconnecting the relay J1 for external load on the voltage transformer T1.

[0074] From the above description, before measurement, the load externally connected to the voltage transformer T1 is disconnected to improve the measurement accuracy.

[0075] The bus cabinet and the measurement method capable of automatically measuring the capacitance current of the power distribution network of the application can be applied to the scene of capacitance current test of the system, and the following specific embodiments are described:

[0076] Please refer to Figures 1 to 4 The embodiment one of the application is:

[0077] A busbar cabinet capable of automatically measuring the capacitor current of a power distribution network, such as Figure 1 and Figure 2 As shown, the system includes a cabinet 1 and measuring equipment. The measuring equipment includes a monitoring host 10, an automatic switch adjustment device, a voltage transformer T1, a capacitance current tester 2, a grounding switch K1, a discharge gap G1, a harmonic suppressor R1, a relay J1, a high-voltage fuse F1, an isolating handcart Q1, and a surge arrester B1. The capacitance current tester 2 includes a control module U1, a display screen 8, and buttons 9. Buttons 9 can be categorized by function, such as a power button and a measurement button.

[0078] like Figures 3 to 5 As shown, the neutral point of the high-voltage winding of voltage transformer T1 is grounded through grounding switch K1. The output terminal of the capacitive current tester 2 is connected to the secondary winding of voltage transformer T1. The automatic switch adjustment device is connected to grounding switch K1. The monitoring host 10 is connected to both the capacitive current tester 2 and the automatic switch adjustment device, and is used to communicate with the remote monitoring platform 12. The input terminal of voltage transformer T1 is used to connect to an external busbar. Figure 4 As shown, windings L1, L2, and L3 are the secondary windings of voltage transformer T1, connected end-to-end to form an open delta configuration, and connected to other loads via control module U1. Windings L4, L5, and L6 are the high-voltage windings of voltage transformer T1. One end of each winding is connected in parallel to form a neutral point, which is connected to grounding switch K1. During capacitance current testing, current is injected into the open delta configuration, generating current signals at the three high-voltage windings. Due to the coupling function between the high-voltage winding and the secondary winding of voltage transformer T1, the feedback signal is coupled to the secondary winding of voltage transformer T1 and fed back to the capacitance current tester 2.

[0079] In this embodiment, as Figure 2 As shown, to facilitate switchgear switching operations, the automatic switchgear adjustment device includes an adjustment motor 11, a rotating shaft 3, and an operating hole 4 located on the cabinet. The rotating shaft 3 is rotatably mounted inside the cabinet at a position corresponding to the operating hole 4 and is fixedly connected to the moving contact of the grounding switch K1. The adjustment motor 11 is connected to the rotating shaft and drives the rotating shaft 3 to rotate. The monitoring host 10 is connected to the adjustment motor 11. When the rotating shaft 3 rotates, it causes the moving contact of the grounding switch K1 to contact or separate from the stationary contact.

[0080] In this embodiment, as Figure 3 As shown, the input terminal of voltage transformer T1 is connected to the busbar in sequence through high-voltage fuse F1 and isolating handcart Q1. The neutral point is grounded through harmonic suppressor R1. Harmonic suppressor R1 has the function of suppressing ferroresonant overvoltage of voltage transformer T1 and can prevent frequent blowing of high-voltage fuse F1. A support insulator is also provided inside cabinet 1 to support the conductors and prevent backflow.

[0081] In the embodiment, as shown in Figure 3 , one end of the discharge gap G1 is connected with the neutral point of the high-voltage winding of the voltage transformer T1, and the other end is grounded. Once the neutral point of the high-voltage winding of the voltage transformer T1 generates an overvoltage, the discharge gap G1 is broken down, thereby being pulled back to zero point by the discharge gap G1.

[0082] In the embodiment, the opening of the voltage transformer T1 is externally connected with a load through the relay J1. When the capacitance current test is performed, the connection of the voltage transformer T1 with other loads is disconnected, thereby improving the accuracy of the measurement.

[0083] In the embodiment, as shown in Figure 2 , the cabinet 1 is divided into a first chamber 5, a second chamber 6 and a third chamber 7. The voltage transformer T1 is located in the first chamber 5, and the grounding knife switch K1 is located in the second chamber 6. One end of the lightning arrester B1 is connected with the bus through an isolation handcart Q1, and the other end is grounded. The lightning arrester B1 specifically uses a lightning arrester cart. The lightning arrester cart is located in the third chamber 7. Moreover, the relay J1 is also provided with an independent chamber, thereby optimizing the equipment layout in the bus cabinet and facilitating the maintenance and management.

[0084] In the embodiment, the output end of the control module U1 is connected with the secondary winding of the voltage transformer T1. The display screen 8 and the button 9 are connected with the control module U1.

[0085] Please refer to Figures 4 to 6 , the second embodiment of the present application is:

[0086] A measurement method of a bus cabinet capable of automatically measuring the capacitance current of a power distribution network, applied to the bus cabinet capable of automatically measuring the capacitance current of the power distribution network of the first embodiment, as shown in Figure 6 , comprising the following steps:

[0087] S1, receiving and executing the knife switch closing instruction of the remote monitoring platform 12, and closing the grounding knife switch;

[0088] In the embodiment, as shown in Figure 5 , the operating personnel performing the capacitance measurement can inform the control personnel in the remote monitoring platform 12 by filling out the work ticket, and the control personnel issues the knife switch closing instruction to the monitoring host 10 in the remote monitoring platform 12, without the measurement personnel going to the site to close the grounding knife switch K1. Moreover, before performing the capacitance current measurement, the relay J1 for externally connecting the load on the voltage transformer T1 needs to be disconnected, so as to improve the measurement accuracy.

[0089] In the embodiment, the specific operation process of closing the grounding knife switch K1 is that the control adjusting motor 11 drives the rotating shaft 3 to rotate, so that the moving contact of the grounding knife switch K1 is in contact with the static contact.

[0090] S2, the capacitor current tester 2 measures the capacitor current of the voltage transformer T1, and reports the measurement result to the remote monitoring platform 12;

[0091] In the embodiment, as shown in the figure, Figure 4 The step S2 is specifically:

[0092] S21, injecting a non-power frequency low voltage signal to the secondary winding of the voltage transformer T1;

[0093] S22, receiving a feedback signal corresponding to the non-power frequency low voltage signal at the secondary winding of the voltage transformer T1;

[0094] S23, obtaining the capacitor current according to the feedback signal.

[0095] In the embodiment, the calculation expression of the capacitor current obtained according to the feedback signal is:

[0096] I=3ωCU;

[0097] Wherein, I represents the capacitor current, C represents the capacitance, and U represents the phase voltage of the measured system.

[0098] S3, receiving and executing the disconnecting instruction of the grounding knife switch K1 of the remote monitoring platform 12, and disconnecting the grounding knife switch K1.

[0099] In the embodiment, the operation of closing the grounding knife switch K1 is similar to the process of disconnecting, which is remotely controlled by the remote monitoring platform 12.

[0100] In summary, the busbar cabinet and the measurement method for automatically measuring the capacitor current of the power distribution network provided by the application connect the grounding knife switch at the neutral point of the high-voltage winding of the voltage transformer connected to the busbar, close the grounding knife switch when testing the capacitor current, and directly measure the capacitor current on the secondary side of the voltage transformer through the capacitor current tester, without complicated switching operation and rewiring. The protector is also provided with discharge gap, lightning arrester, isolation switch and other protection devices, the display screen and the button are arranged on the capacitor current tester, the internal space of the cabinet is optimized by the chamber design, the grounding knife switch can be remotely and automatically controlled by the remote monitoring platform, and the measurement data can be obtained, so that the operation steps of the voltage transformer capacitor current test of the busbar cabinet are simplified, the work difficulty of the operator is reduced, the work efficiency is improved, and the convenience and safety of the work are improved.

[0101] The above is only an embodiment of the application, and does not limit the patent range of the application, and any equivalent transformation or direct or indirect application in related technical field based on the content of the specification and drawings of the application is also included in the patent protection range of the application.

Claims

1. A measurement method of a busbar cabinet capable of automatically measuring a capacitive current of a power distribution network, characterized by, The busbar cabinet comprises: a cabinet body and a measuring device in the cabinet body, the measuring device comprising a voltage transformer, a monitoring host, an automatic regulating device for a switch, a capacitance current tester and a grounding switch; a neutral point of a high-voltage winding of the voltage transformer is grounded through the grounding switch, and an output end of the capacitance current tester is connected with a secondary winding of the voltage transformer; the automatic regulating device for the switch is connected with the grounding switch; the monitoring host is connected with the capacitance current tester and the automatic regulating device for the switch respectively, and is used for communicating with a remote monitoring platform; an input end of the voltage transformer is used for external connection of a busbar; the measuring method comprises the following steps: S1, receiving and executing a switch closing instruction of the remote monitoring platform to close the grounding switch; S2, measuring a capacitance current of the voltage transformer by the capacitance current tester, and reporting a measurement result to the remote monitoring platform; S3, receiving and executing a switch opening instruction of the remote monitoring platform to open the grounding switch.

2. The measuring method of the busbar cabinet capable of automatically measuring a capacitance current of a distribution network according to claim 1, wherein the automatic regulating device for the switch comprises a regulating motor, a rotating shaft and an operating hole on the cabinet body; the rotating shaft is rotatably arranged in the cabinet body at a position corresponding to the operating hole, and is fixedly connected with a moving contact of the grounding switch; the regulating motor is connected with the rotating shaft and drives the rotating shaft to rotate; the monitoring host is connected with the regulating motor; the rotating shaft drives the moving contact of the grounding switch to contact or separate from a stationary contact when rotating; the closing of the grounding switch specifically comprises: controlling the regulating motor to drive the rotating shaft to rotate, so that the moving contact of the grounding switch contacts the stationary contact.

3. The measuring method of the busbar cabinet capable of automatically measuring a capacitance current of a distribution network according to claim 1, wherein the capacitance current tester comprises a control module, a display screen and a button; an output end of the control module is connected with the secondary winding of the voltage transformer; the control module is connected with the monitoring host, the display screen and the button respectively; the step S2 specifically comprises: S21, injecting a non-power frequency low-voltage signal into the secondary winding of the voltage transformer; S22, receiving a feedback signal corresponding to the non-power frequency low-voltage signal at the secondary winding of the voltage transformer; S23, obtaining the capacitance current according to the feedback signal.

4. The measuring method of the busbar cabinet capable of automatically measuring a capacitance current of a distribution network according to claim 1, wherein the measuring device further comprises a relay; an opening of the voltage transformer is externally connected with a load through the relay; the step S2 further comprises, before the step S2: opening the relay for externally connecting a load on the voltage transformer.

5. The method of claim 1, wherein the method further comprises: determining the capacitance current of the busbar cabinet by using the capacitance current of the busbar cabinet and the voltage of the busbar cabinet. the measuring device further comprises a discharge gap; one end of the discharge gap is connected with the neutral point of the high-voltage winding of the voltage transformer, and the other end is grounded.

6. The measuring method of the busbar cabinet capable of automatically measuring the capacitive current of the power distribution network according to claim 1, characterized in that, the measuring device further comprises a harmonic eliminator; the neutral point is grounded through the harmonic eliminator.

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