Active quitting method for active injection full-compensation arc suppression coil

An arc suppression coil, active technology, applied in emergency protection circuit devices for limiting overcurrent/overvoltage, emergency treatment AC circuit layout, electrical components, etc., to achieve the effect of suppressing resonance

CN112467733AActive Publication Date: 2021-03-09STATE GRID HENAN ELECTRIC POWER ELECTRIC POWER SCI RES INST +1
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2021-03-09

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Abstract

The invention discloses an active quitting method for an active injection full-compensation arc suppression coil, and belongs to the technical field of power distribution fault maintenance. In the grounding residual compensation process, a single-phase voltage source inverter is controlled to additionally inject active current with a variable periodic amplitude into a neutral point, which is equivalent to adding a damping resistor Rs in a parallel resonance circuit and is used for damping resonance of the arc suppression coil and a capacitor, so that rapid quitting of the active full-compensation arc suppression coil after a grounding fault is recovered is realized; a zero-sequence current path equivalent model after the grounding fault of the power distribution network is recovered is established; a relationship between a drop amplitude and time under a zero-sequence voltage is established through the zero-sequence current path equivalent model; the injected active current drops alongwith the drop of the zero-sequence voltage, the voltage of the neutral point drops below the threshold value, and the single-phase voltage source inverter is controlled to quit operation. Therefore,the active quitting of the arc suppression coil can be realized after the fault of the grounding wire is fully compensated.
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Description

technical field

[0001] The invention relates to the technical field of power distribution fault maintenance, in particular to a method for actively withdrawing active power injection fully compensated arc suppression coils. Background technique

[0002] With the increasing capacity of urban distribution network and the large increase of nonlinear loads and cable lines, while the magnitude of the ground fault current is increasing, the residual current component it contains is also greatly increasing, while the traditional arc suppressing coil The active component and harmonic component in the ground fault current cannot be compensated, which makes it difficult to control the ground residual current within the specified range. A large residual current will cause the arc to be unable to be extinguished in time, which seriously threatens the safe operation of the power grid and also poses a huge threat to personal safety. Therefore, active arc suppression based on full compensa...

Examples

Embodiment 1

[0048] A method for actively withdrawing from an active power injection fully compensated arc suppression coil, comprising the following steps:

[0049] S1: In the process of ground residual compensation, by controlling the single-phase voltage source inverter to inject additional periodic active current with variable amplitude to the neutral point, it is equivalent to adding damping resistance R in the parallel resonant circuit s , used to suppress the resonance between the damping arc suppression coil and the capacitor, and realize the rapid exit of the active full compensation arc suppression coil after the ground fault is restored;

[0050] S2: Establish the equivalent model of the zero-sequence current path after the ground fault recovery of the distribution network;

[0051] S3: Through the equivalent model of the zero-sequence current path in S2, establish the relationship between the zero-sequence voltage drop amplitude and time;

[0052] S4: The injected active curre...

Embodiment 2

[0078] The active power injection full-compensation arc suppressing coil active withdrawal method of the embodiment of the present invention differs from the first embodiment in that:

[0079] In S1, the grounding residual compensation process is as follows: the residual current full compensation device is mainly composed of a master-slave arc suppression coil and a single-phase inverter. The arc-suppression coil uses an automatic turn-adjusting arc-suppression coil as the main arc-suppression coil, and the controllable part of the single-phase inverter as the slave arc-suppression coil. The main arc-suppression coil compensates most of the fundamental ground current, and the compensation current is generated from the arc-suppression coil through the single-phase inverter by using PWM control technology. As a beneficial supplement to the main arc-suppression coil, it compensates for the remaining fundamental ground current harmonic components in .

[0080] When the distributi...

example

[0133] Taking the 10kV distribution network with three-circuit outlet system as an example, the system design is carried out.

[0134] (1) Calculation of ground capacitance

[0135] After considering the single-phase grounding, the grounding current is 60A, then the calculated value of the capacitance can be

[0136]

[0137] (2) Calculation of the inductance value of the main arc suppression coil

[0138] According to the parallel resonance theory of inductors and capacitors, the theoretical inductance value can be obtained as:

[0139]

[0140] In practice, the main arc suppression coil is generally in an overcompensated state, that is, the detuning degree γ<0, according to the calculation formula of the detuning degree:

[0141]

[0142] For different degrees of detuning there are:

[0143]

[0144] From this, the formula for calculating the overcompensation inductance value is:

[0145]

[0146] (3) Calculation of line grounding resistance

[0147] The ...