CN219533220U

CN219533220U - Ground fault active full compensation device capable of disturbing line selection

Info

Publication number: CN219533220U
Application number: CN202320209823.XU
Authority: CN
Inventors: 高志辉; 张振江; 王军超
Original assignee: HEBEI XUHUI ELECTRIC CO Ltd
Current assignee: HEBEI XUHUI ELECTRIC CO Ltd
Priority date: 2023-02-14
Filing date: 2023-02-14
Publication date: 2023-08-15
Anticipated expiration: 2033-02-14

Abstract

The utility model discloses a ground fault active full compensation device capable of disturbing line selection, which comprises a controller and an active power compensator, wherein the output end of the active power compensator is connected with an injection transformer, one end of the primary side of the injection transformer is grounded, and the other end of the primary side of the injection transformer is connected with a grounding transformer through a high-voltage switch; the circuit between the high-voltage switch and the grounding transformer is provided with a voltage transformer for measuring the zero sequence voltage of the system, each circuit connected with the system bus is respectively provided with a current transformer for measuring the zero sequence current of the circuit, and the output ends of the voltage transformer and the current transformer are respectively connected with the input end of the controller. The utility model adopts the active power compensator to perform disturbance for line selection, and utilizes the characteristic that the amplitude and the phase of the output voltage of the active full compensation device are adjustable to perform disturbance calculation for multiple times, thereby improving the number of samples, eliminating partial accidental factors and effectively improving the line selection accuracy.

Description

Ground fault active full compensation device capable of disturbing line selection

Technical Field

The utility model relates to the technical field of single-phase grounding protection of power distribution networks, in particular to a full compensation device.

Background

The active full compensation device for the ground fault generally comprises a power transformer, a step-up transformer, a vacuum contactor, an Active Power Compensator (APC), a controller and the like, when a single-phase ground fault occurs, the controller adjusts the output voltage of the active power compensator, can compensate the voltage and the current of the single-phase ground fault point to be close to 0, thoroughly eliminates arc light when the single-phase ground fault occurs, and can also perform accurate line selection by utilizing a disturbance mode, thereby being an optimal scheme for solving the single-phase ground fault.

The main differences between a faulty line and a non-faulty line are: (1) the zero sequence current flowing through the fault line is the system residual current, the zero sequence current of other lines is the ground capacitance current of the fault line, and the capacitance current is possibly equal to the residual current due to the fact that the residual current is not fixed, so that the fault line cannot be used as the basis for judging the line; (2) the ground resistance of the fault line is one more ground resistance than the other lines, so that the line selection can be started from the ground resistance. In the system provided with the grounding fault active full compensation device, the controller can conveniently adjust the output voltage, and generate disturbance to the system to select a fault grounding line. In the process of line selection, partial patents distinguish fault lines and non-fault lines by comparing the change quantity of the zero sequence current of the lines in a full compensation state and other states, or distinguish by comparing the zero sequence current phases; however, both methods bring in reactive current components with larger amplitudes, resulting in small variable duty cycles and less pronounced characteristic quantities. In addition, the judgment is performed only by one comparison, so that the accidental increase is caused, and the accuracy of line selection is also affected.

Disclosure of Invention

The utility model aims to solve the technical problem of providing a ground fault active full compensation device capable of disturbing line selection, which is used for carrying out line selection by disturbing generated by the change of the amplitude and the phase of output voltage and improving the accuracy of line selection.

In order to solve the technical problems, the technical scheme adopted by the utility model is as follows.

The active full compensation device for the ground fault capable of disturbing line selection comprises a controller and an active power compensator, wherein the active power compensator is respectively connected with the controller and a ground transformer connected to a system bus; the output end of the active power compensator is connected with an injection transformer, one end of the primary side of the injection transformer is grounded, and the other end of the primary side of the injection transformer is connected with a grounding transformer through a high-voltage switch; the circuit between the high-voltage switch and the grounding transformer is provided with a voltage transformer for measuring the zero sequence voltage of the system, each circuit connected with the system bus is respectively provided with a current transformer for measuring the zero sequence current of the circuit, and the output ends of the voltage transformer and the current transformer are respectively connected with the input end of the controller.

By adopting the technical scheme, the utility model has the following technical progress.

The utility model adopts the active power compensator to perform disturbance for line selection, and utilizes the characteristic that the amplitude and the phase of the output voltage of the active full compensation device are adjustable to perform disturbance calculation for multiple times, thereby improving the number of samples, eliminating partial accidental factors and effectively improving the line selection accuracy.

Drawings

FIG. 1 is a system wiring diagram of the present utility model;

fig. 2 is a flow chart of the present utility model when selecting lines.

Wherein: jdb. ground transformer; apc, active power compensator; KM. high voltage switch; kzq. controller; zrb injection transformer; PT. voltage transformer; CT01-CT0n. Current transformer 01-0n; Z1-Zn. Line impedance; rd. ground resistance.

Detailed Description

The utility model will be described in further detail with reference to the drawings and the detailed description.

The active full compensation device for the ground fault capable of disturbing line selection comprises a controller KZQ, an active power compensator APC, an injection transformer ZRB, a high-voltage switch KM, a voltage transformer PT and a plurality of current transformers CT01-CT0n. The device is applied to a system with n lines, and the system wiring of each electrical device is shown in fig. 1, and is specifically as follows.

The grounding transformer JDB is connected to a system bus, and the active power compensator APC is respectively connected with the controller KZQ and the grounding transformer JDB; the output end of the active power compensator APC is connected to the controlled end of the injection transformer ZRB, one end of the primary side of the injection transformer ZRB is grounded, and the other end is connected to the grounding transformer JDB through the high-voltage switch KM.

The voltage transformer PT is arranged on a line between the high-voltage switch KM and the grounding transformer JDB and is used for measuring the zero sequence voltage of the system; the current transformers CT01-CT0n are respectively arranged on each line connected with the system bus and are used for measuring the zero sequence current of the line; the output ends of the voltage transformer PT and the current transformer are respectively connected with the input end of the controller KZQ.

After the system suffers from single-phase earth fault, the controller judges the phase and controls the APC output of the active power compensator to compensate the active current, reactive current and harmonic current of the system, and the system enters a full compensation state.

In the full compensation state, the controller collects the zero sequence currents of all lines and the zero sequence voltage of the system, and calculates the active components or the active power of the zero sequence currents; then controlling the voltage change output by the active power compensator, collecting the zero sequence current of all lines and the zero sequence voltage of the system again, and calculating the active component or active power of the zero sequence current; and then calculating the ratio of the difference value of the active components or the active power of the zero sequence current of each line before and after the output voltage is regulated to the value before regulation. After 3 times of adjustment and 3 times of calculation, if the ratio of the difference value of a certain line in 2 times is the maximum and exceeds a threshold value, judging the line as a grounding line; if the proportion of all the differences does not exceed the threshold value, the bus is determined to be grounded.

The specific disturbance decision line flow Cheng Ru of the present utility model is shown in fig. 2, and the detailed method is as follows.

(1) First disturbance

At this time, the controller collects zero sequence currents of all lines: i01_1, i02_ … … i0n_1, zero sequence voltage u0_1 of the system, and zero sequence current active components of each line are calculated through fourier transformation: i01re_1, i02re_1 … … i0nre_1.

The amplitude or phase of the output voltage of the active power compensator APC is adjusted, and the amplitude and phase-adjusted amplitude can be set in advance by the controller. After the system is stable, the controller collects the zero sequence currents of all lines: i01_2, i02_ … … i0n_2, zero sequence voltage u0_2 of the system, and calculating the zero sequence current active components of each line through fourier transformation: i01re_2, i02re_2 … … i0nre_2.

Calculating the zero sequence active component difference ratio: k1 = (i01re_2-i01re_1)/i01re_1, k2= (i02re_2-i02re_1)/i02re_1 … … kn= (i0nre_2-i0nre_1)/i0nre_1.

The maximum kx is found from the zero-sequence active component difference ratios k1, k2 … … kn and compared with the threshold value ks.

(2) Second disturbance

The amplitude or phase of the APC output voltage of the active power compensator is regulated, so that the system is restored to a full compensation state, and the active components of the zero sequence currents of all lines are collected and calculated; according to the set value, the amplitude or phase of the output voltage is adjusted for the second time, and the active components of the zero sequence currents of all lines are collected and calculated; and calculating the zero sequence active component difference ratio again, finding out the maximum value, and comparing with a threshold value.

(3) Third disturbance

Repeating the step (2), calculating the zero sequence active component difference ratio for the 3 rd time, finding out the maximum value, and comparing with the threshold value.

The amplitude or phase of the output voltage of the active power compensator APC is adjusted to restore the system to a fully compensated state.

(4) Line judgment

If the maximum value of the difference ratio of the active components in the two times is larger than the threshold value in the three times of calculation and the active components are the same circuit, the circuit is a grounding circuit; if the proportion of all the differences does not exceed the threshold value, the bus is determined to be grounded.

In the utility model, the threshold value, the disturbance times and the judgment times can be modified into other values according to actual conditions. The utility model can also use zero sequence active power to judge the line, and the method is the same as the zero sequence current active component.

The utility model utilizes the characteristic of adjustable voltage of the active full compensation device, can perform multiple disturbance calculation, improves the number of samples, can exclude partial accidental factors, and can effectively improve the line selection accuracy.

The above-described embodiments are merely preferred embodiments of the present utility model, and it should be noted that it will be apparent to those skilled in the art that several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be regarded as the scope of the utility model.

Claims

1. The active full compensation device for the ground fault capable of disturbing line selection comprises a controller (KZQ) and an Active Power Compensator (APC), wherein the Active Power Compensator (APC) is respectively connected with the controller (KZQ) and a ground transformer (JDB) connected to a system bus; the method is characterized in that: the output end of the Active Power Compensator (APC) is connected with an injection transformer (ZRB), one end of the primary side of the injection transformer (ZRB) is grounded, and the other end of the primary side of the injection transformer is connected with a grounding transformer (JDB) through a high-voltage switch (KM); the high-voltage power supply is characterized in that a voltage transformer (PT) for measuring the zero sequence voltage of the system is arranged on a line between the high-voltage switch (KM) and the grounding transformer (JDB), current transformers for measuring the zero sequence current of the line are respectively arranged on each line connected with a system bus, and output ends of the voltage transformer (PT) and the current transformers are respectively connected with an input end of a controller (KZQ).