CN201887444U - Electric grounding comprehensive protector for TXHPT - Google Patents

Abstract

The utility model relates to an electric grounding comprehensive protector for TXHPT, mainly comprising a comprehensive protection multifunctional control unit MCU and a PT (potential transformer) device, wherein the comprehensive protection multifunctional control unit MCU is connected with the PT device through an electric wire, and the other end of the PT device is connected with a resistor FU1 which is connected in parallel with a resistor FU2; one end of the resistor FU2 is provided with a switch and connected with a system bus, and the other end of the resistor FU2 is connected with a group of six-phase combined overvoltage protector; and one end of the six-phase combined overvoltage protector is connected with a device capable of causing electric arcs. The electric grounding comprehensive protector for TXHPT has the advantages of especially distinguishing imperceptible weak signals of earth fault with high resistance, such as scraping and touching and broken lines of overhead lines by tree branches, insulation moisture and aging of cables in cable lines and the like, and eliminating the faults in the bud.

Description

TXHPT electricity consumption grounding comprehensive protecting device device

Technical field:

The utility model relates to a kind of be applied to isolated neutral system, functions such as collection extinguishing arc, route selection, harmonic elimination, PT switching are the integrated protection equipment of one.

Background technology:

In the running of electric power system, the time regular meeting break down, the operating experience of electric power system shows that the most of fault in the electric power system is a single phase ground fault.China 3～35kV (containing 66kV) power distribution network, most neutral non-effective grounding modes that adopt.Along with the megatechnics transformation of city net and rural power grids, increasing power distribution network has been realized cableization, and earthing capacitance current also significantly increases thereupon.In city net 10kV system, compare with the overhead transmission line of equal length, the capacitance current of cable line is bigger more than 20 times than the capacitance current of overhead transmission line, so that when single-phase arc grounding fault takes place, the electric arc of fault point is difficult to extinguish, and produces the overvoltage up to 3.15～3.5 times of phase voltages, threatens the equipment of the insulation fragility of system, tend to develop into phase fault, even cause the ill effect of " baked wheaten cake is operated ".

The existing operating standard regulation of China to the electrical network of 3～35kV (containing 66kV) neutral point indirect earthing, when earth fault takes place, allows to continue operation two hours, as through the approval of higher level relevant department, can also prolong.But rules are not done for the notion of " single phase ground fault " and are clearly defined, as single phase ground fault is metallic earthing, the fault phase voltage reduces to zero, all the other two voltage to earths that perfect phase will be increased to line voltage, thereby the insulation against ground level of the electric equipment of this class electrical network such as transformer, voltage/current instrument transformer, circuit breaker and cable etc., all should be able to satisfy the requirement of bearing the effect of line voltage for a long time and not damaging.But, if single phase ground fault is an arc grounding, then its overvoltage is generally 3.15～3.5 times phase voltage, under high like this overvoltage continuous action, certainly will cause the accumulation damage of solid insulation, in the sound weak link that forms insulation mutually, and then develop into phase fault and cause serious accident.

Along with the development of urban and rural power grids, overhead transmission line is progressively replaced by the cable line of solid insulation.Because the build-up effect that solid insulation punctures, its internal overvoltage, particularly arc grounding overvoltage that produces during electrical network generation single phase intermittent arc grounding and the ferro-resonance over-voltage that excites have thus become one of this class electric power netting safe running and have threatened greatly.Wherein serious with single-phase arc grounding overvoltage.It is saturated that the arc grounding overvoltage can make voltage transformer take place, and excites ferro resonance, causes voltage transformer seriously to transship, and causes fuse blows or instrument transformer to burn.Because arc grounding overvoltage longer duration, energy very easily surpass the ability to bear of lightning arrester, cause accidents such as Explosion of on Arrester.

The utility model content:

The utility model provides a kind of electricity consumption grounding comprehensive protecting device, particularly a kind of electricity consumption grounding comprehensive protecting device by TXHPT

Main feature of the present utility model is: mainly by integrated protection multifunctional controller MCU; the PT device; wherein integrated protection multifunctional controller MCU connects the PT device by electric wire; the other end of PT device connects a resistance FU1; resistance FU1 and resistance FU2 are connected in parallel; end at resistance FU2 is provided with a switch; and be connected with system busbar; the other end of resistance FU2 is connected with one group of six combined formula overvoltage protection device; six combined formula overvoltage protection device one ends connect the device that can cause electric arc; six zinc oxide assemblies are installed in the iron base; between the alternate and phase ground zinc oxide assembly is arranged all, the protection fuse places zinc oxide to set up the upper end.

The beneficial effects of the utility model are: especially can differentiate the small-signal that is difficult to discover high resistance earthing fault, extension as the branch in the overhead transmission line bumps, the cable insulation in the broken string, cable line makes moist, aging or the like, fault is eliminated in bud.

Description of drawings:

Fig. 1: the utility model schematic diagram

Fig. 2: extinguishing arc and route selection schematic diagram

Fig. 3: the record ripple figure of reactor pressure limiting extinguishing arc

Fig. 4: adopt reactor to eliminate the record ripple figure of high resistance earthing fault

Fig. 5: device is to the protection preparation of system

Fig. 6: simple resonant circuit figure

Fig. 7: main, backup protection action sequence

Embodiment:

1, reactor working earthing

Reactor reliably is connected with the standard earthing device of transformer station, and its contact resistance＜1.5m Ω belongs to working earthing.Mutually by the reactor quiet earth, earth current constitutes the loop by the earth mat-reactor-fault phase bus of transformer station with fault in protection, and current in the fault point is approximately zero, consequently eliminates or the inhibition fault protection person and device security.Protection causes the maximum rising of earth mat current potential much smaller than the regulation permissible value, in the safe range of various voltages, to the no any harmful effect of safety in the transformer station.

2, phase fault safeguard measure

2.1 the fail safe of criterion

The utility model can be by the criterion of distinctive voltage, electric current, guarantees that reactor only throws one-phase ground protection, never malfunction when phase fault takes place.

2.2 reactor restriction phase fault electric current

The long-term galvanization ability of reactor, drops into reactor protection continuously and gets rid of until fault when guaranteeing under system's maximum operational mode single phase ground fault to take place greater than 100A～300A (can select as required) in the time of can growing.

If the phase just in case miscarry, or the out-phase ground short circuit takes place, the existence of reactor can suppress the phase fault electric current.For the 10kV system, reactor can be limited in short circuit current about 3kA.

2.3 the breaking current scope that fast current-limiting fuse and zero sequence overcurrent protection constitute

Fast current-limiting fuse: reactor be in series with fast current-limiting fuse FU2 mutually between the power supply, when phase fault takes place, can cut off electric current, the assurance system safety greater than 3Ie～63kA.

Zero sequence overcurrent, protection locking: (1.2～3Ie) time, the utility model is involution at once, this function and current limiting fuse composition classification phase fault fast tripping protection greater than the zero-sequence current set point when the electric current that flows through reactor.

3, self check, the device abnormal alarm

The utility model device is monitored the main protection executive component of self by the switching value input port in the controller: the protection actuating relay of vacuum contactor and controller, form good self-checking function, and in case note abnormalities, report to the police immediately.

Claims (3)

1.TXHPT electricity consumption grounding comprehensive protecting device device; mainly by; integrated protection multifunctional controller MCU, PT device; wherein integrated protection multifunctional controller MCU connects the PT device by electric wire; the other end of PT device connects a resistance FU1; resistance FU1 and resistance FU2 are connected in parallel; end at resistance FU2 is provided with a switch; and be connected with system busbar; the other end of resistance FU2 is connected with one group of six combined formula overvoltage protection device, it is characterized in that: six combined formula overvoltage protection device one ends connect the device that can cause electric arc.

2. TXHPT electricity consumption grounding comprehensive protecting device device according to claim 1 is characterized in that six zinc oxide assemblies on the overvoltage protection device are installed in the iron base.

3. TXHPT electricity consumption grounding comprehensive protecting device device according to claim 1 is characterized in that between the phase ground zinc oxide assembly being arranged all in the alternate and protective device of arc-initiating device.

Images