CN205583702U - Novel reactive compensation device - Google Patents

Abstract

The utility model provides a novel reactive compensation device, including reactive compensation unit, biasing electric capacity unit, current transformer, voltage transformer and controller, the reactive compensation unit includes a plurality of parallel connection's reactive compensation branch road, and each reactive compensation branch road includes fuse, switch and reactive compensation capacitor bank respectively, and every reactive compensation capacitor bank comprises the electric capacity that triangle -shaped connects, (i) A (i) the looks generating line, (i) B (i) the looks generating line, (i) (i) the looks generating line through corresponding fuse and switch, is connected to reactive compensation capacitor bank respectively to C, biasing electric capacity unit includes switch and biasing capacitor bank, the biasing capacitor bank comprise star connection's electric capacity, the neutal point earthing, (i) A (i) the looks generating line, (i) B (i) the looks generating line, (i) (i) electric capacity is connected through corresponding switch respectively to C to the looks generating line, current transformer with side joint of voltage transformer is on the generating line, and the secondary side is connected to the controller, the controller is connected to the switch in switch and the biasing electric capacity unit in each reactive compensation branch road.

Description

A kind of novel reactive power compensator

Technical field

This utility model relates to power system reactive power compensation appliance arrangement technical field, a kind of novel reactive power compensator.

Background technology

In order to improve reliability and the seriality of power supply, China's low and medium voltage distribution network many employings isolated neutral mode in early days, When there is singlephase earth fault, in the case of electric network capacitance and current is little, ground arc can self-extinguishment, power distribution network can tape jam Continue power supply 1～2 hour.Along with in the development of China's power distribution network, particularly urban distribution network, the ratio of cable run is increasingly Height, direct-to-ground capacitance is on the increase, and causes circuit when there is singlephase earth fault, and the capacitance current flowing through trouble point is greatly increased. Can reliably extinguish in order to ensure the various ground arcs occurred in electrical network, when system capacitive current is more than the limit value of regulatory requirements, Arc suppression coil must be installed with compensation of ground capacitance current.The capacitance current of power distribution network is accurately measured and is determined whether to install arc suppression coil And determine the premise of arc suppression coil reasonable compensation capacity.

Owing to urban power distribution network development in the last few years is very fast, capacitance current speedup is accelerated, and needs the most continually to power distribution network electric capacity Electric current measures.Usually using the direct method of measurement in actual power distribution network, not only operation and wiring are complicated, and are likely to result in Ungrounded phase insulation weakness damages thus causes line to line fault, threatens the safe operation of distribution system, is therefore not suitable for using Direct method measures work frequently.More popular in theoretical research is injecting signal, but the specialty that the method needs Measuring instrument, and certainty of measurement is affected relatively big by unbalanced power supply degree, needs to design power frequency notch filter to filter power frequency component Interference.

Utility model content

Measuring capacitance current the most easily, this utility model provides the idle of a kind of band capacitance current of distribution network measurement Compensation device, adding one group on reactive power compensator can be with the Capacitor banks of split-phase switching, Capacitor banks Y-connection, neutral point Ground connection.

This utility model solves its technical problem and be employed technical scheme comprise that a kind of novel reactive power compensator, including idle benefit Repay unit, partially installing capacitor unit, current transformer, voltage transformer and controller,

Described reactive compensation unit includes some the reactive-load compensation branch roads being connected in parallel, each reactive-load compensation branch road include respectively fuse, Switch and compensation capacitors, the electric capacity C that each compensation capacitors is connected by triangle_Ai、C_BiAnd C_CiConstitute, A phase bus, B phase bus, C phase bus, respectively through corresponding fuse and switch, are connected to compensation capacitors；

Described partially installing capacitor unit includes switch and bias capacitor group, and described bias capacitor group is by the electric capacity C of Y-connection_A、C_B And C_CConstituting, neutral ground, A phase bus, B phase bus, C phase bus connect electric capacity C through respective switch respectively_A、C_B、 C_C；

Described current transformer and described voltage transformer primary side are connected on bus, and secondary side is connected to controller；

Controller is connected to the switch in each reactive-load compensation branch road and the switch in partially installing capacitor unit.

And, A phase bus is connected to electric capacity C_AiAnd C_CiBetween, B phase bus is connected to electric capacity C_AiAnd C_BiBetween, C phase is female Line is connected to electric capacity C_BiAnd C_CiBetween.

The partially installing capacitor being used for measuring capacitance current of distribution network is integrated into reactive-load compensation dress by of the present utility model having the technical effect that In putting so that use New Reactive Power Compensation Device of the present utility model when carrying out the reactive-load compensation needed for system, moreover it is possible to support to use In on-line measurement capacitance current of distribution network, measure work process principle simple, safe and reliable, workable, not only have relatively High certainty of measurement, and do not affect normal work and the safe and stable operation of system of reactive power compensator.

Accompanying drawing explanation

The structural representation of Fig. 1 this utility model embodiment.

The measurement of Fig. 2 this utility model embodiment uses schematic diagram.

Detailed description of the invention

Technical solutions of the utility model are described in detail below in conjunction with drawings and Examples.

As it is shown in figure 1, a kind of band capacitance current of distribution network measure novel reactive power compensator, including reactive compensation unit, Partially installing capacitor unit, current transformer TA, voltage transformer TV and controller.Described reactive compensation unit has some parallel connections The reactive-load compensation branch road connected, each reactive-load compensation branch road is constituted by fuse, switch and compensation capacitors, i-th The electric capacity C that compensation capacitors is connected by triangle_Ai、C_Bi、C_Ci(i=1,2,3 ...) constitute, A phase bus, B Phase bus, C phase bus, respectively through corresponding fuse and switch, are connected to compensation capacitors, and wherein A phase bus connects In C_AiAnd C_CiBetween, B phase bus is connected to C_AiAnd C_BiBetween, C phase bus is connected to C_BiAnd C_CiBetween；Described partially Putting capacitor cell and constitute with bias capacitor group by switching, described bias capacitor group is by the electric capacity C of Y-connection_A、C_B、C_C Constituting, neutral ground, A phase bus, B phase bus, C phase bus connect electric capacity C through respective switch respectively_A、C_B、C_C； Described current transformer and described voltage transformer primary side are connected on bus, and secondary side is connected to controller, is used for measuring three-phase Line current and bus phase voltage；Controller is connected to all above-mentioned switches, including the switch in each reactive-load compensation branch road and biased electrical Hold the switch in unit, in addition to the normal switching controlling reactive compensation unit, moreover it is possible to control partially installing capacitor unit according to measurement requirement Split-phase switching.When being embodied as, those skilled in the art can arrange control realization mode according to prior art.

Use a kind of New Reactive Power Compensation Device that the present embodiment is provided, in addition to normal work carries out reactive-load compensation, additionally it is possible to use In the measurement carrying out system capacitive current.Capacitance current measurement function is come real mainly by partially installing capacitor unit and voltage transformer Existing.Principle uses Biased capacitor method measure the capacitance current of power distribution network, directly utilize the reactive-load compensation capacitor on bus Measurement of correlation is realized, it is to avoid the potential safety hazard brought when being biased electric capacity on bus with voltage transformer, operation safety, Convenient, and there is higher precision.

For the sake of ease of implementation, it is provided that use the provided reactive power compensator of the present embodiment to measure the work of capacitance current of distribution network Make process, comprise the following steps:

1) system is in normal operating condition, during the normal grid-connected work of reactive power compensator, and record A phase voltage U now_A； When reactive power compensator is in normal operating conditions, bias capacitor C_A、C_B、C_CAll do not put into.

2) C is controlled by controller_AThe switch Guan Bi at place, by the partially installing capacitor C of A phase_AAccess A phase bus, treat voltage stabilization After, record A phase voltage U now_A’；

When accessing partially installing capacitor, system neutral voltage can raise.When being embodied as, partially installing capacitor C_A(C_BAnd C_C) Capacitance those skilled in the art can preset appropriately sized according to experiment or experience voluntarily, crosses conference and neutral point voltage is substantially risen The 15% of height, even more than phase voltage, capacitance is chosen too small, can bring bigger measurement error, typically take C_A=C_B=C_C=1 μ F is the most suitable.

3) power distribution network ground capacity C can be calculated according to following formula_0A:

$C_{0A}=\frac{U_A^{\′}}{U_A-U_A^{\′}}\×C_A$

4) by step 1), 2), 3) described in operation be repeated once B, C are biphase, calculate C_0BAnd C_0C, average C₀=(C_0A+C_0B+C_0C)/3；

In order to reduce unbalanced power supply degree to the impact of measurement result and other measurement error, carry out phase at A, B, C three-phase Same measurement operation, averages to the line mutual-ground capacitor tried to achieve, better.

5) according to formula I_C=ω C₀U_φ, can be with calculation system capacitive earth current I_C。

In above formula, ω is electrical network power frequency angular frequency,For the specified phase voltage of electrical network.

Above-mentioned steps 3) principle as follows:

Use the principle of this utility model measurement device capacitance current of distribution network as in figure 2 it is shown, it is partially installing capacitor (C_A) two ends Thevenin equivalent circuit.Partially installing capacitor accesses the busbar voltage (U that open-circuit voltage is this phase at front two ends_A), equivalent internal resistance is electricity The zero sequence direct-to-ground capacitance C of net₀, after accessing partially installing capacitor, the voltage at partially installing capacitor two ends becomes U_A', have according to voltage divider principle:

$U_A^{\′}=\frac{C_A}{C_{0A}+C_A}\×U_A$

Thus can be in the hope of:

$C_{0A}=\frac{U_A^{\′}}{U_A-U_A^{\′}}\×C_A$

As seen from the above analysis, use the model that this utility model measurement device capacitance current of distribution network is used in principle Being accurate, result of calculation has higher precision.

This utility model claims circuit hardware design, is not related to the improvement of software aspects.

It is emphasized that embodiment described in the utility model is illustrative rather than determinate.Therefore this practicality is new Type includes the embodiment being not limited to described in detailed description of the invention, every by those skilled in the art according to skill of the present utility model Other embodiments that art scheme draws, also belong to the scope of this utility model protection.

Claims (2)

1. a novel reactive power compensator, it is characterised in that: include reactive compensation unit, partially installing capacitor unit, current transformer, Voltage transformer and controller,

Described reactive compensation unit includes some the reactive-load compensation branch roads being connected in parallel, each reactive-load compensation branch road include respectively fuse, Switch and compensation capacitors, the electric capacity C that each compensation capacitors is connected by triangle_Ai、C_BiAnd C_CiConstitute, A phase bus, B phase bus, C phase bus, respectively through corresponding fuse and switch, are connected to compensation capacitors；

Described partially installing capacitor unit includes switch and bias capacitor group, and described bias capacitor group is by the electric capacity C of Y-connection_A、C_B And C_CConstituting, neutral ground, A phase bus, B phase bus, C phase bus connect electric capacity C through respective switch respectively_A、C_B、 C_C；

Described current transformer and described voltage transformer primary side are connected on bus, and secondary side is connected to controller；

Controller is connected to the switch in each reactive-load compensation branch road and the switch in partially installing capacitor unit.

The most novel reactive power compensator, it is characterised in that: A phase bus is connected to electric capacity C_AiAnd C_Ci Between, B phase bus is connected to electric capacity C_AiAnd C_BiBetween, C phase bus is connected to electric capacity C_BiAnd C_CiBetween.