CN201312112Y

CN201312112Y - Overvoltage monitoring and comprehensive protective device for medium voltage power network

Info

Publication number: CN201312112Y
Application number: CNU2008201994090U
Authority: CN
Inventors: 徐成飞
Original assignee: Individual
Current assignee: Anhui Is An Electric Co Ltd
Priority date: 2008-12-03
Filing date: 2008-12-03
Publication date: 2009-09-16
Anticipated expiration: 2018-12-03

Abstract

The utility model relates to an overvoltage monitoring and comprehensive protective device for a medium voltage power network, in particular to a controllable three-phase combined overvoltage protector. The protector comprises a unit protector formed by four large-capacity zinc oxide nonlinear resistors, a pulse current sensor and a high-speed switch, wherein, one ends of the four unit protectors are connected together to form a four-star type structure, the lower ends of the three stars respectively penetrate the pulse current sensor, the upper ends of the three stars are respectively connected at the lower end head of a high-voltage isolating switch, and the other star is connected with high-speed switch in parallel and is grounded. The utility model can keep various over-voltage of the medium voltage power network with the voltage of 3 to 35 KV to a minimum and can effectively limit and eliminate the over-voltage caused by the single-phase intermittent arc grounding and the resonance.

Description

Medium voltage network over-voltage monitoring and comprehensive protector

Technical field

The utility model relates to a kind of 3～35KV medium voltage network that is used for; to lightning overvoltage, the switching overvoltage of this class electrical network, particularly single-phase indirect arc grounding surge and resonance overvoltage provide a kind of medium voltage network over-voltage monitoring and the comprehensive protector of reliably protecting.

Background technology

6～35kv medium voltage network overvoltage mainly is divided into lightning overvoltage, switching overvoltage, power-frequency overvoltage, arc grounding overvoltage and resonance overvoltage; Wherein arc grounding overvoltage and resonance overvoltage are frequent in normal emerged in operation, and its harmfulness is bigger, and overvoltage is in case generation often causes electric equipment to damage and large-area power outage.Because resonance and arc grounding overvoltage are longer action time, give and select the safeguard measure aspect to cause difficulty.Overvoltage protection device is an overvoltage protection of electric applicance, and still there is the overvoltage protection problem in himself.If power-frequency overvoltage, arc grounding overvoltage and resonance overvoltage enter protector protection active region, perseveration damages blast until thermal runaway in the time of certainly will growing.If select gapless zinc oxide overvoltage protection device for use, must improve its rated voltage and continuous operating voltage, improve the safety of himself, this certainly will make residual voltage raise, and protective value reduces; If select the zinc oxide overvoltage protection device of band series gap for use, must improve the discharge voltage in gap, cut off arc grounding overvoltage and resonance overvoltage, make that frequent overvoltage occurring can not get protection, has reduced the fail safe of whole electrical network.

Summary of the invention

At the deficiencies in the prior art, the utility model provide a kind of can be with all kinds of overvoltage Limiting of 3～35KV medium voltage network to minimum, and can effectively limit and eliminate the overvoltage comprehensive protector that single-phase indirect arc ground connection and resonance cause.

The utility model is achieved through the following technical solutions:

Medium voltage network over-voltage monitoring and comprehensive protector, comprise high voltage isolator respectively with controlled three phase combined over-voltage protector and antiresonance voltage mutual inductor serial, described controlled three phase combined over-voltage protector, can hold the cell protection device that znr constitutes greatly by four, pulses of current sensor and high-speed switch are formed, four cell protection device one ends link together and form four stars type structure, wherein the Samsung lower end is passed pulses of current sensor respectively, the upper end is connected to the lower end of high voltage isolator respectively, other star high-speed switch ground connection in parallel; Described high-speed switch constitutes four stars shape structure by three single-phase high-speed switches, a high-voltage and current-limitation fuse and a current transformer; Described antiresonance voltage transformer is formed four stars shape structure by voltage transformer, high-tension fuse, resonance eliminator high-speed switch in parallel; Microcomputerized controller is made up of microprocessor, imput output circuit and button display circuit, and its input circuit is connected with voltage transformer, current transformer and pulse current instrument transformer secondary output, and its output circuit is connected with a high-speed switch deciliter coil.

The utility model can effectively arrive minimum voltage levvl with normal operating all kinds of overvoltage Limiting; the insulation fault that causes because of overvoltage is greatly reduced; can monitor overvoltage generation information in real time; reach analysis; the effect of preventing accident and taking place; can effectively suppress the overvoltage that single-phase indirect arc ground connection of 3～35KV medium voltage network and resonance cause; improved the service conditions of electrical network; the probability that no gap metal zinc oxide lightning arrester (MOA) is had an accident greatly reduces; the mechanism of its overvoltage protection and the size of electrical network are irrelevant; thereby the influence that not enlarged by the change of power system operating mode and electrical network; big and small networks all can use; whole device is formed a high-voltage board; simple in structure; volume is little, installs; debugging is convenient, and is cheap; safe in utilization, can be widely used in the high pressure station-service system in 3～35KV transformer station and power plant.

Description of drawings

Accompanying drawing is an electrical block diagram.

Embodiment

Shown in accompanying drawing.

Medium voltage network over-voltage monitoring and comprehensive protector comprise controlled three phase combined over-voltage protector 1, antiresonance voltage transformer 2, combination phase-splitting control type rapid arc extinction switch 3, microcomputerized controller 4, high voltage isolator 5.Controlled three phase combined over-voltage protector 1 can hold cell protection device RA ~ RD, pulses of current sensor TA ~ TC and the high-speed switch KD that znr constitutes greatly by four and form, four cell protection device one ends link together and form four stars type structure, wherein the Samsung lower end is passed pulses of current sensor TA ~ TC respectively, the upper end is connected to the lower end of high voltage isolator 5 respectively, other star high-speed switch KD in parallel ground connection; Antiresonance voltage transformer 2 by be connected into star threephase potential transformer PT, three-phase connect respectively high-tension fuse FU2 ~ FU4, star point meets resonance eliminator RX and high-speed switch KX forms; Described combination phase-splitting control type rapid arc extinction switch 3 is formed four stars type structure by three high-speed switch KA ~ KC and high-voltage and current-limitation fuse FU1, and wherein ground unit passes current transformer CT; Described microcomputerized controller is made of microprocessor, input and output and button display circuit, its input connects with secondary output, current transformer CT and the pulses of current sensor TA ~ TC secondary output of voltage transformer pt respectively, and the output of microcomputerized controller connects with deciliter coil of five high-speed switches.When electrical network normally moves, microcomputerized controller control KD, KX closure, KA ~ KC disconnects, and the rated voltage of controlled three phase combined over-voltage protector 1 can be with all kinds of overvoltage Limiting to minimum by the phase voltage design; Antiresonance voltage transformer 2 can correctly be changed the electrical network phase voltage; When electrical network generation single-phase earthing or resonance fault, the control switch KD of the controlled three phase combined over-voltage protector 1 of microcomputerized controller 4 controls disconnects, guarantee voltage protector 1 inherently safe, the variation of three-phase voltage U a, Ub, Uc and residual voltage U0 instantaneous value that while microcomputerized controller 4 provides according to voltage transformer 2 is judged, and according to the result who judges, send corresponding instruction: if the fault that takes place is a unstable arc ground connection, microcomputerized controller 4 is after judging ground connection separate, send instruction, the crowbar switch closure of the fault phase of order; Make system be quickly converted to the direct ground connection of stable metallicity by instable arc grounding, the fault phase voltage reduces to zero, and electric arc disappears, and after the predefined time of delaying time, the crowbar switch of open failure phase is finished extinguishing arc again; If the fault that takes place is a resonance, microcomputerized controller 4 sends instruction, makes KX disconnect, and inserts resonance eliminator RX, carries out harmonic elimination.

Claims

1, medium voltage network over-voltage monitoring and comprehensive protector, comprise high voltage isolator respectively with controlled three phase combined over-voltage protector and antiresonance voltage mutual inductor serial, it is characterized in that described controlled three phase combined over-voltage protector, can hold the cell protection device that znr constitutes greatly by four, pulses of current sensor and high-speed switch are formed, four cell protection device one ends link together and form four stars type structure, wherein the Samsung lower end is passed pulses of current sensor respectively, the upper end is connected to the lower end of high voltage isolator respectively, other star high-speed switch ground connection in parallel; Described high-speed switch constitutes four stars shape structure by three single-phase high-speed switches, a high-voltage and current-limitation fuse and a current transformer; Described antiresonance voltage transformer is formed four stars shape structure by voltage transformer, high-tension fuse, resonance eliminator high-speed switch in parallel; Microcomputerized controller is made up of microprocessor, imput output circuit and button display circuit, and its input circuit is connected with voltage transformer, current transformer and pulse current instrument transformer secondary output, and its output circuit is connected with a high-speed switch deciliter coil.