CN104377706A

CN104377706A - Opening method for reactive compensation capacitor bank

Info

Publication number: CN104377706A
Application number: CN201410449600.6A
Authority: CN
Inventors: 杜钦君
Original assignee: Shandong University of Technology
Current assignee: Shandong University of Technology
Priority date: 2014-09-05
Filing date: 2014-09-05
Publication date: 2015-02-25

Abstract

The invention provides an opening method for a reactive compensation capacitor bank and belongs to the field of power quality of electrical power systems. In order to restrain rush current and overvoltage which are generated during opening of the reactive compensation capacitor bank, the opening method used when both the value of the voltage of the reactive compensation capacitor bank and the value of the voltage of a power grid are peak values or trough values. According to the opening method for the reactive compensation capacitor bank, the optimum opening phase positions of all phases of capacitor banks are designed according to the actual connection mode of the capacitor banks, and the minimum delay time required from the moment an opening signal is received to the moment the on-off action is triggered is calculated according to the intrinsic opening time of a switch and external factors. Compared with other opening methods, the opening method for the reactive compensation capacitor bank has the advantages that the voltage change ratio is lowered under the same opening time deviation condition, rush current and overvoltage which are generated during opening of the capacitor bank are reduced, power quality is improved, and the opening method has an extremely good application prospect on the occasion that reactive compensation is conducted by means of the capacitor bank.

Description

A kind of separating brake method of compensation capacitors

Technical field

The invention provides a kind of separating brake method of compensation capacitors, belong to electric power quality field.

Background technology

In electric power system, normally Stochastic sum is uncertain for the separating brake phase place of compensation capacitors, very high the shoving and overvoltage of amplitude can be produced in the moment of separating brake, in order to meet power network development and power consumer to the demand of high-quality, highly reliable power supply, separating brake should be reduced shove and overvoltage, prevent arc reignition and bang.

Summary of the invention

The object of this invention is to provide one and can overcome above-mentioned defect, propose a kind of separating brake method of compensation capacitors, separating brake when compensation capacitors and line voltage are all peak value or trough, can effectively reduce to shove and overvoltage, its technology contents is:

A kind of separating brake method of compensation capacitors, separating brake when compensation capacitors and line voltage are all peak value or trough, according to the connected mode of Capacitor banks, design the best separating brake phase place of each phase Capacitor banks, according to intrinsic opening time and the extraneous factor of switch, calculate the minimum delay time received needed for sub-gate signal to trigger switch activation, each phase Capacitor banks is separated in optimum phase, suppress to shove and overvoltage;

Star neutral grounding capacitor component lock method is at the current zero-crossing point of each phase by Capacitor banks separating brake, selects reference voltage to be , Capacitor banks separating brake order is B phase, A phase, C phase successively, relative to nearest one zero point phase place, three-phase current is respectively delayed through the phase place of zero crossing , with ;

Star isolated neutral Capacitor banks separating brake control method is first in current zero-crossing point separating brake one phase, then time delay in the cycle, by rear two-phase separating brake simultaneously, selection reference voltage is , first A phase separating brake, separating brake when then B phase is identical with C, relative to nearest one zero point phase place, the phase place of three-phase current zero passage is delayed respectively , with .

The present invention compared with prior art, makes each phase Capacitor banks of reactive power compensation at optimum phase separating brake, can effectively suppress to shove and overvoltage, improves the safety of network system.

Accompanying drawing explanation

Fig. 1 is the separating brake sequential of star neutral grounding capacitor group.

Fig. 2 is the separating brake sequential of star isolated neutral Capacitor banks.

In figure: for reference signal, for separating brake instruction is apart from the time at previous Voltage Reference zero point, , , be respectively delayed trigger time during each phase separating brake, , , be respectively the intrinsic opening time of each phase, t _arcfor the arcing time.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described:

A kind of separating brake method of compensation capacitors, separating brake when compensation capacitors and network system voltage are all peak value or trough, for the neutral ground of Shunt Capacitor Unit star and star isolated neutral connected mode, design the best separating brake phase place of each phase Capacitor banks respectively;

Fig. 1 is the separating brake sequential of neutral grounding capacitor group, and as can be seen from Figure 1, reference voltage is chosen to be , assuming that the arcing time is 5ms, Capacitor banks separating brake order is B phase, A phase, C phase successively, relative to nearest one zero point phase place, three-phase current is delayed respectively through the phase place of zero crossing and arc extinction , with , suppose moment receives separating brake instruction, can calculate the minimum delay time of threephase switch contact required for the disconnection of optimum target phase place place to be:

In formula, f is mains frequency, for separating brake instruction is apart from the time at previous Voltage Reference zero point, for Switch Three-Phase opening time, for the arcing time, n is for ensureing minimum positive integer, get 1 or 2.

Fig. 2 is the separating brake sequential of isolated neutral capacitance group, and as seen from Figure 2, selection reference voltage is , assuming that Capacitor banks separating brake order is followed successively by A phase, B phase, C phase when the arcing time is 5ms; Relative to nearest one zero point phase place, the phase place of the current over-zero of three-phase and arc extinction is delayed respectively , with , suppose moment receives separating brake instruction, calculates the minimum delay time of threephase switch contact required for the disconnection of optimum target phase place place to be:

Claims

1. the separating brake method of a compensation capacitors, compensation capacitors and line voltage are all separating brake control method when peak value or trough, it is characterized in that: according to the connected mode of Capacitor banks, design the best separating brake phase place of each phase Capacitor banks, according to intrinsic opening time and the extraneous factor of switch, calculate the minimum delay time received needed for sub-gate signal to trigger switch activation, each phase Capacitor banks is separated in optimum phase, suppress to shove and overvoltage;