CN2515851Y - Earth leakage protective device for coal mine underground - Google Patents

Abstract

Disclosed is a leakage protection device used in an underground coal mine, relating to a safety protection device of a power supply system. The utility model comprises a mobile transformer (KBSGZY) and a high-voltage side circuit including a high-voltage vacuum breaker (GD) and a high-voltage power network protector (GZBD-1). A secondary transforming side of the mobile transformer of a low-voltage side circuit is three-phase and four-wire system, and the low-voltage circuit is connected with a zero-sequence reactor (DK) and a low-voltage power network protector (DZB-II); the low-voltage protector is connected with the high-voltage protector (GZBD-1) through terminals (3,4) by leads. The utility model provides possibility for the electric appliances of a system with effectively earthed neutral (a plurality of points) to be used in a system with non-effectively earthed neutral, not only improving the function for protection safely and reliably but also solving the matching problem scientifically and facilitating field applications.

Description

Earth leakage protective device under the coal mine

One, technical field

The utility model belongs to the safety guard of colliery underground power supply system, relates to a kind of earth leakage protective device that is applicable to electric power system isolated neutral and two kinds of forms of neutral ground.

Two, background technology

When cutting coal under the coal mine, can produce inflammable, explosive gas and coal dust, can fire immediately when they run into very hot oven, power is huge, and greatly destructive to mine and people's life, therefore, the down-hole allows to produce naked light anything but.The reason that naked light produces is a lot, and wherein supply line and power supply unit are the main paties that produces naked light, and electric power system is the essential condition of Coal Production, so only under limited case, use electric power system, could guarantee the safety in production of mine.This just needs the safety guard of electric power system, and wherein earth leakage protective is main contents.It is by a kind of device, the detection that supply line and equipment are leaked electricity, when its insulation values over the ground descends, when producing leakage current value above required standard, just can drive circuit breaker automatically and force to have a power failure, block up and cut off very hot oven, when measured value to be checked is normal, can continue to send electricity, guarantee the safety of mine.

At present, the electric power system under the coal mine has two kinds of forms, and a kind of is electric power system isolated neutral mode, claims the single-point grounding protection system again, and another kind is the electric power system neutral grounding mode, claims the multipoint earthing protection system again.China adopts the former, adopts the latter as English, moral, the U.S. abroad.Because the detection of electrical leakage standard and the form of dual mode are different, therefore, its electricity consumption product can not use in the other side's system, otherwise, can be considered as leak current fault and open circuit protection by the other side's system.Lift example explanation: at the down-hole fully-mechanized mining working; use homemade flameproof mining mobile transformer substation; output 3.3KV voltage; connect the TD3.3 type magnetic starter of Britain Brnsh company; control homemade TY900 type coal-winning machine, at this moment, the protective device of mobile substation can be thought leak current fault; implement earth leakage protective, so this supporting mode can not be worked.Because the domestic magnetic starter of also not producing the 3.3KV system in order to address the above problem, can only be removed the earth leakage protective device of magnetic starter now at present, adopt higher level's special anthorization policy to use.This not only uses the scene and brings inconvenience, and has caused the incomplete shortcoming of system's earth leakage protective.

Three, summary of the invention

The purpose of this utility model is to overcome above-mentioned shortcoming; a kind of earth leakage protective device is provided; make the electric equipment of earth neutral system; can in the system of isolated neutral, use; not only perfect defencive function; reach safe and reliable effect, and scientifically solved on-the-spot matching used problem.

The utility model is achieved through the following technical solutions.Earth leakage protective device under a kind of coal mine comprises: phase shifting transformer, contain the high-pressure side circuit of high-pressure vacuum breaker and grid system integrated protector and lower-voltage circuit.It is characterized in that described lower-voltage circuit; the outlet method of the secondary side of its phase shifting transformer is a three-phase four-wire system; be a, b, c, o; and be connected to the zero-sequence reactor of detection of electrical leakage; it is connected with low-voltage network comprehensive protection device; the low-voltage comprehensive protector is connected to the change over switch of single-point, multipoint earthing system, and low-voltage network comprehensive protection device is connected with grid system integrated protector with lead by binding post.Described zero-sequence reactor, i.e. sensor for detecting electric leakage, its primary side one end is connected with the neutral point o of phase shifting transformer, and the other end detects (direct current detection) signal input part with the single-point of low-voltage network comprehensive protection device and is connected; Secondary side detects (exchange and detect) signal input part and is connected with the multiple spot of low-voltage network comprehensive protection device.The primary side of zero-sequence reactor is connected to the knob that single-point grounding system is simulated manual testing circuit, and secondary side is connected to manual testing circuit of multipoint earthing system simulation and knob, and primary side also is connected to the logical capacitance of handing over.Described low-voltage network comprehensive protection device is a kind of low-voltage control circuit that contains single-chip microcomputer, is provided with the feedback signal output; Be provided with single-point, multipoint earthing system detection signal input; Be provided with the selection signal end that is connected with change over switch (diverter switch of single-point, multipoint earthing system selection mode), and the earth terminal of protector.

The utility model has following beneficial effect against existing technologies:

Owing in the low-pressure side major loop, be provided with detection of electrical leakage, judgement, analysis circuit, isolated neutral system and grounding system detection electric leakage signal organically combined.It is earlier by change over switch selective system mode; detect electric leakage signal by testing circuit again; if electric leakage is arranged; send the earth fault signal by the leakage protection module circuit analysis of low-voltage network comprehensive protection device, after judging; and by output; export the high pressure comprehensive protection device to by lead, drive the high-pressure vacuum breaker outage, realized earth leakage protective.The core of testing circuit is sensor for detecting electric leakage (DK); its design links together single-point, multipoint earthing protection system; realize the purpose that the electric equipment in the earth neutral system can use in isolated neutral system, below its principle of division and effect:

The principle of single-point grounding protection system is to adopt the direct current detection mode, judges by detecting DC current values whether system has earth fault, process: protect (DZB-II) output direct current 40V voltage → transducer (DK) → transformer neutral point 0 → 3.3KV electrical network by combining.If when following, direct current detects electric current will be greater than the established standards current value to 50K Ω for 3.3KV electrical network insulation against ground resistance drop, DZB-II combines guarantor'ss earth leakage protective action, and output E3, E2 send signal, and the primary cut-out disconnection reaches the purpose of power-failure protecting.

The principle of multipoint earthing protection system is to adopt to exchange detection mode, is to utilize to exchange neutral point current potential floating property, makes corresponding judgment.Process: during the circuit fault-free, the three-phase electricity direct-to-ground capacitance equates, load is symmetrical, the current potential of transformer neutral point 0 and earth potential equate that the current potential of transformer neutral point 0 and earth potential are equal, so, transformer neutral point 0 → relay (ZJ1-2) → transducer (DK) → logical capacitance (the C1) → ground of handing over, do not have alternating current to flow through, combining guarantor's terminal (D7, D17) does not just have ac induction voltage yet, is normal condition.When electrical network has phase ground connection or insulation values to reduce; there are not direct-to-ground capacitance or direct-to-ground capacitance to reduce; promptly produce leakage current; the three-phase resultant load impedance is asymmetric; the current potential of transformer neutral point or rising or reduction; be that neutral point 0 and ground potential are different; alternating voltage is arranged between them; so there is alternating current to flow through; the DK secondary side just induces alternating voltage, when leakage current greater than 75mA; the DK secondary side produces 4V voltage, and low-voltage variation device DZB-II judges that immediately earth fault is arranged; and make corresponding execution action, send signal and drive the circuit breaker outage; realized earth leakage protective.

In sum; the utility model is that the electric equipment of earth neutral system can use in the system of isolated neutral; safe and reliable technical scheme is provided; not only perfect defencive function; and scientifically solved the supporting middle practical difficulty problem that exists of prior art, made things convenient for on-the-spot use.

Four, description of drawings

Fig. 1 is an electrical principle block diagram of the present utility model; among the figure: the GD-high-pressure vacuum breaker; the SQ-no-voltage release; TQ electromagnetism shunt release; the GZBD-1-grid system integrated protector, DZB-II-low-voltage network comprehensive protection device, KBSGZY-phase shifting transformer; DK-zero-sequence reactor (sensor for detecting electric leakage), SYA-is single, multipoint earthing system change over switch.

Fig. 2 is the circuit diagram of the earth leakage protective device under a kind of coal mine.

Five, embodiment

Below by embodiment, be further described in conjunction with the accompanying drawings.

As shown in Figure 1, 2, the earth leakage protective device under a kind of coal mine is the high-pressure side circuit in the left side of phase shifting transformer KBSGZY, and the right side is a lower-voltage circuit.The high-pressure side circuit contains high-pressure vacuum breaker GD and grid system integrated protector GZBD-1.Physical circuit is as follows: the input of 6KV high pressure A, B, C three-phase electricity; under high voltage isolator GK, meet high-pressure vacuum breaker GD; be connected to: cross high pressure protective resistance RY1-3; overcurrent, short-circuit sensor CT1, CT2, CT3; power direction selection ground protection circuit sensor OLH; the insulation monitoring line protective circuit of high-tension cable is connected with transformer KBSGZY primary side.Also be connected to the auxiliary transformer PT that the 100V operating voltage is provided for the high and low pressure control circuit in the high pressure main circuit, and fuse RD1.High-voltage control circuit is the grid system integrated protector GZBD-1 that contains single-chip microcomputer; be provided with: operating voltage input ZB8, ZB18; over-current signal input ZB7, ZB17, ZB6, ZB16; power direction selection ground signalling input ZB5; low pressure feedback signal input ZB11, ZB14, binding post ZB10, the ZB20 of circuit breaker drive circuit and drive coil, ZB9 etc.The low-pressure side physical circuit is as follows: phase shifting transformer KBSGZY secondary side outlet method is a three-phase four-wire system, i.e. a, b, c, o, and wherein o is a zero line, its purpose is exactly for realizing the detection of multipoint earthing system.Be connected to sensor for detecting electric leakage (being zero-sequence reactor) DK at transformer KBSGZY secondary side; primary side one end of zero-sequence reactor is connected with the neutral point 0 of phase shifting transformer KBSGZY; the other end is connected with the single-point detection signal input D14 of low-voltage network comprehensive protection device DZB-II, and the secondary side of zero-sequence reactor DK is connected with multiple spot detection signal input D7, the D17 of low-voltage network comprehensive protection device DZB-II.Low-voltage network comprehensive protection device DZB-II is connected with the change over switch SYA of single-point, multipoint earthing system selection mode, low-voltage network comprehensive protection device by binding post 3 with 4 and lead-in wire be connected with grid system integrated protector GZBD-1.Low-voltage network comprehensive protection device is a kind of low-voltage control circuit that contains single-chip microcomputer, is provided with feedback signal lead-out terminal E2, E3; Be provided with the detection signal input terminal D14 of single-point system and multipoint system detection signal input terminal D7, D17 and earth terminal E1.Zero-sequence reactor DK primary side is connected to single-point analogue detection circuitry LDA1 and Tong Jiao capacitance C1, and secondary side is connected to multiple spot analogue detection circuitry LDA2 and terminals E4.Lower-voltage circuit also is provided with overcurrent, overload, short circuit, open phase protection transducer CT1, CT2, CT3, and it is D10, D1, D2, D3 that corresponding low pressure is combined the signal input terminal of protecting device; Also be provided with cable insulation detecting sensor UGSP, it is E11 that corresponding low pressure is combined the signal input terminal of protecting device; Also be provided with low-pressure side voltage indication transformer TB1, high direct voltage testing circuit TB2,2CL, R4 etc.

Claims (4)

1; earth leakage protective device under a kind of coal mine; comprise: phase shifting transformer (KBSGZY); the high-pressure side circuit that contains high-pressure vacuum breaker (GD) and grid system integrated protector (GZBD-1); and the lower-voltage circuit on phase shifting transformer right side; it is characterized in that: described lower-voltage circuit; the outlet method of its phase shifting transformer (KBSGZY) secondary side is three-phase four-wire system (a; b; c; o); be connected to zero-sequence reactor (DK); zero-sequence reactor is connected with low-voltage network comprehensive protection device (DZB-II); low-voltage network comprehensive protection device is connected to single-point; the change over switch of multipoint earthing system (SYA), low-voltage network comprehensive protection device is by binding post (3; 4) be connected with grid system integrated protector with lead.

2, according to the described earth leakage protective device of claim 1, it is characterized in that: described zero-sequence reactor (DK), its primary side one end is connected with the neutral line (o) of phase shifting transformer (KBSGZY), and the other end is connected with the single-point detection signal input (D14) of low-voltage network comprehensive protection device (DZB-II); Secondary side is connected with the multiple spot detection signal input (D7, D17) of low-voltage network comprehensive protection device.

3, according to the described earth leakage protective device of claim 1; it is characterized in that: described low-voltage network comprehensive protection device (DZB-II); it is a kind of low-voltage control circuit that contains single-chip microcomputer; be provided with feedback signal input terminal (E2, E3); be provided with single-point system detection signal input terminal (D14) multipoint system detection signal input terminal (D7, D17); be provided with the selection signal terminal (E10, E8, E7) that is connected with change over switch (SYA), and the earth terminal of protector (E1).

4, according to the described earth leakage protective device of claim 2, it is characterized in that: described zero-sequence reactor (DK), its side joint have single-point analogue detection circuitry (LDA1) and the logical capacitance (C1) of handing over; Secondary side is connected to multiple spot analogue detection circuitry (LDA2).

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