Integrated protector for program-controlled high-voltage switch
The present invention relates to a kind of high-voltage switch gear comprehensive protector, confession, power transformation system integrated protector for program-controlled high-voltage switch under particularly a kind of coal mine.
At present, the high-voltage switch gear protective device of colliery down-hole application is handled and monitor protection short-circuit signal, overload signal, current mode electric leakage signal, power direction type electric leakage signal, insulating performance of cable signal etc. respectively with analogue technique.For example, realize that short circuit, overload protection are by simulation technology commonly used such as semiconductor device, R-C network, integrated operational amplifier the load current secondary AC signal by instrument transformer output to be carried out processing such as rectification, filtering, carry out level ratio then.When signal level surpassed the overload setting value, overload time-delay door was opened, and to the delay circuit charging that R, C form, when delay circuit charging back level reaches or surpasses the current potential of adjusting in advance, made certain level upset drive the relay of operating a switch and finish protection work.Under load-side was short-circuited situation, signal level reached or when surpassing the short circuit setting value, its level upset drives the relay of operating a switch and finishes protection work.
But the high-voltage switch gear protective device of this employing analogue technique has following defective:
1. adopt the high-voltage switch gear protective device of analogue technique not carry out oneself's detection, also can not when operation, show the working condition of self, therefore can't avoid operating with failure for a long time critical piece.
2. this high-voltage switch gear protective device function is few, only has the most basic defencive functions such as short-circuit protection, overload protection, current mode earth leakage protective, power direction type earth leakage protective, cable insulation monitor protection.
3. inherent accuracy is low, and repetitive error is big, and consistency is poor, and time stability and temperature stability are poor, and sensitivity and antijamming capability condition each other, and tripping, malfunction problem are many.
4. alarm free function.
5. there is not digital Presentation Function.
6. there is not communication capacity.
7. failure cause can only be checked once, is unfavorable for accident analysis.
The object of the present invention is to provide a kind of integrated protector for program-controlled high-voltage switch that adopts digital technology.
Another object of the present invention provides a kind of integrated protector for program-controlled high-voltage switch that is applicable to the colliery underground work that uses shield technology.
Integrated protector for program-controlled high-voltage switch of the present invention adopts following measure to realize.In this comprehensive protector, comprise: signal attenuation circuit, filter circuit, rectification circuit, multiplexed signal sampling circuit.Analog-digital converter circuit, central controller (single-chip microcomputer), human-computer dialogue circuit, mnemon, digital display driver unit, switch motion control and parts such as fair driver element, communications interface unit and power subsystem; It is characterized in that: under the control of central controller, multiplexed signal sampling circuit and analog-digital converter circuit are transformed to digital signal with each road analog signal and directly deliver to central controller and handle, and perhaps will directly deliver to central controller by the switching value signal of circuit such as rectification output and carry out signal processing.Described central controller can be various eight, the single-chip microcomputer of sixteen bit, and described central controller can be made into chip piece with analog-digital converter circuit; Perhaps described central controller also can be made into chip piece with memory and mnemon.
Integrated protector for program-controlled high-voltage switch of the present invention; adopt the can isolation technology; so that interfere with electromagnetic field is played shielding action; its method is; can is covered on the central controller, and make can ground connection, below central controller; utilize the ground wire of the Copper Foil formation of printed board, so that play shielding action for interfere with electromagnetic field greater than the area of central controller.In addition, also can cover on can on the monoblock wiring board at central controller place, so that play shielding action to interfere with electromagnetic field, this wiring board can be connected with lead by aperture with connection between other circuit board.
Integrated protector for program-controlled high-voltage switch of the present invention; be applicable to that operating voltage is in the high-pressure vacuum switch of high pressure for flame-proof type in, the power transformation system under the coal mine of 6000V, also go in the high-pressure vacuum switch of high pressure under the coal mine that operating voltage is 10000V for flame-proof type in, the power transformation system.
The operation principle of integrated protector for program-controlled high-voltage switch of the present invention is described with reference to Fig. 1 now.When comprehensive protector of the present invention powers up start or resets when starting, central controller is at first carried out to the self check of this machine and to the inspection of peripheral circuits, carries out human-computer dialogue subsequently, to determine action and action setting value, changes protection work operation then over to.The groundwork of this comprehensive protector is that the flow chart according to Fig. 2 carries out, and shows failure code when self check has fault, when the self check fault-free, shows complete " 8 " and the reason of operating a switch last time, and enters the monitoring state.At this moment, when being in normal operating conditions, then show the current value of primary voltage value and load as if load-side; When if load-side is in the abnormal work state,, send the order of operating a switch after the identification repeatedly filling in the time of being permitted, and, show the reason that this is operated a switch to higher level's report, monitor whether load-side really throws off, when load is not thrown off, carry out twice impact and operate a switch, so that load is thrown off; If comprehensive protector breaks down, then show insignificant character or do not have demonstration.
Owing to adopted digital technology in comprehensive protector of the present invention, and the identification that has strengthened in program interference signal detects ability, therefore, the tripping rate, the malfunction rate just reduces greatly, and correctness and reliability increase substantially.Because the present invention has startup self-detection and the expressive ability when allowing to do to reset self check and faults itself when uninterrupted service; avoided the phenomenon of comprehensive protector tape jam work, its fault shows and the long-term memory ability provides convenience for accident analysis.In addition, every protection setting value scope of the present invention is wide, adaptability is strong, is convenient to on-the-spot the use.Digital Presentation Function replaces the interior ammeter of high-voltage switch gear, voltmeter, kilowatt-hour meter or the like.The warning function that the present invention has can reduce the staff's of transformer station inspection workload, special after the getting working face to no communication equipment carries out error protection transformer station's acquired information immediately so that in time fix a breakdown.The present invention monitors automatically, controls automatically for realization under coal mine and Long-distance Control is laid a good foundation.
Fig. 1 is the operation principle block diagram of comprehensive protector of the present invention;
Fig. 2 is the groundwork flow chart of comprehensive protector of the present invention:
Fig. 3 is the operation principle block diagram of the most preferred embodiment of comprehensive protector of the present invention;
Fig. 4 is the operation principle block diagram of another most preferred embodiment of comprehensive protector of the present invention;
Fig. 5 is the schematic diagram to the central controller shielding of comprehensive protector of the present invention;
Fig. 6 is the schematic diagram to the monoblock line plate shielding at the central controller place of comprehensive protector of the present invention;
Below in conjunction with accompanying drawing comprehensive protector of the present invention is described in further detail.
With reference to accompanying drawing 1; when high-voltage fence is the external circuit power supply; each instrument transformer becomes secondary singal with the relevant signal transformation in each road; and deliver to the input of comprehensive protector; then; this input signal is through the multichannel attenuator circuit; filter circuit and rectification circuit are decayed respectively; filtering and rectification; at that time; central controller; be the various signals of single-chip microcomputer to input; (the output signal after the rectification circuit rectification for example; signal through the output of signal multi pass acquisition circuit; digital signal after analog to digital conversion; perhaps by the switching value signal of rectification circuit output), carry out digital logical operation; analyze and judge the signal that needs, carry out computing and the result of computing is input to the display driver unit respectively; switch motion control and driver element; communications interface unit.In normal circumstances, line voltage and load current value are delivered to display unit (perhaps delivering to communication interface circuit simultaneously), at any time show power supply and load running situation, single-chip microcomputer is made different processing according to the reason of fault when fault takes place, and result is delivered to switch motion control and driver element, digital display unit, mnemon and communication interface unit.
Fig. 2 is a groundwork flow chart of the present invention, has done detailed description in the technical scheme of foregoing invention.
Referring now to Fig. 3; external circuit among Fig. 3 comprises: the shielding heart yearn of screened cable and ground wire, high-voltage fence A phase current mutual inductor, C phase current mutual inductor, zero sequence current mutual inductor; and the three-phase and five-pole transformer residual voltage signal of drawing and 10000V or 6000V are transformed to the transformer of 100V; comprehensive protector of the present invention is protected the circuit and the equipment of high-voltage switch gear load-side, will describe the ruuning situation that this comprehensive protector is protected below.
At first describe the overload of A, C phase and the ruuning situation that short circuit is protected; as shown in Figure 3, when high-voltage fence A, C phase output AC electricity, A, C phase current mutual inductor induction secondary current signal; send into comprehensive protector inlet, be respectively V through decay and conversion or voltage signal
A, V
C, again with V
A, V
CDeliver to separately R-L-C filter network through short-channel and overload passage, the filtering high-frequency signal, and after the resistor network decay, deliver to variable connector, modulus (A/D) converter (example 0809) is transformed into digital quantity with analog quantity in the A/D converter, at that time, the sampling rate of central controller (single-chip microcomputer) control A/D converter is read in central controller with A/D converter digital quantity, and this digital quantity is handled (as the r.m.s. computing etc.) and obtained effective value V
A, V
CV
A, V
CThe overload that is provided with mutually with A, C and the pre-tuning value of short circuit compare respectively separately.If when the short-circuit signal passage finds that the continuous signal period complete more than two surpasses the pre-tuning value; promptly be determined and short circuit occurs; so central controller will start the protection operation program, for example output operate a switch signal, start alert program and go to send alarm signal, start communication program and carry out record in the failure logging unit.If when not finding to surpass the short circuit predetermined value; then compare with overload pre-tuning value; if when the signal on the overload passage surpasses overload pre-tuning value; promptly be determined and overload occurs; central controller does not send guarded command, carries out inverse time-lag but start delay circuit, when the moment that arrives inverse time-lag; just start various programs such as protection operation program, accident is handled.If do not surpass overload pre-tuning value, then respectively with V
A, V
CBe transformed into current value separately, deliver to display unit respectively and show load current value.
The ruuning situation of the insulation monitoring protection of the shielding core of present description screened cable, ground wire; monitor protection is to the monitoring of cable bad degree and protection; employed high-tension cable is through special processing in high-voltage fence; insulated electro class value between its shielding heart yearn and the ground wire changes with damaged condition is different; when insulating resistance value drops to a certain degree; should protect as less than 4K Ω the time; when disconnected thigh or phenomenon of rupture appear in cable; its loop resistance will strengthen;, should protect during greatly to a certain degree at loop resistance for example greater than 1.2K Ω.
Comprehensive protector is exported a direct current signal to the screen of cable; when insulating resistance value between the core of shielded type cable, the ground wire reaches the above-mentioned resistance that needs protection; because the insulating resistance value of cable descends and the loop resistance value strengthens; current potential between its core, the ground wire changes; this current potential is delivered to the A/D converter; read in by central controller then; and will be worth with the insulation resistance and the loop resistance predetermined value that set in advance and compare; if insulating resistance value surpasses predetermined value, then need to judge again.If be defined as when unusual, then central controller starts various programs such as protection operation program, and accident is handled.When if the loop resistance value surpasses predetermined value, determine that through judging again when unusual, central controller starts various programs such as protection operation program, accident is handled, thereby protected.
Earth leakage protective is then described.Judge that grid power leakage has two kinds of methods: one, zero-sequence current type back-and-forth method; Two, zero-sequence current, residual voltage power direction type back-and-forth method.Zero-sequence current type back-and-forth method is that the size according to zero-sequence current has judged whether that electric leakage takes place.When single-phase earthing took place, zero-sequence transformer obtained zero-sequence current alternating signal I
oBehind R-L-C network attenuation filter; deliver to a certain signal input part of variable connector; by this road signal of central controller program control gating; be sent to the A/D converter, the signal after the conversion is read in by central controller, after being similar to above-mentioned overload or short circuit processing; (at the earth leakage protective calculation process of zero sequence drying method) works as I
oWhen relatively surpassing, then start timer and delay time, carry out the earth leakage protective processing up to starting protection operation program supervisor with zero-sequence current pre-tuning value.If I
oDo not surpass zero-sequence current pre-tuning value, then continue circulating sampling, repeat said procedure.
Further describe the earth leakage protective ruuning situation of power direction type again; as shown in Figure 3; the residual voltage signal of drawing by the three-phase and five-pole transformer in the high-voltage switch gear; through R-L-C network dividing potential drop; deliver to the another signal input of multiway analog switch after the filtering; this signal gating of central controller program control; and deliver to the A/D converter; carry out the A/D conversion; central controller is by the earth leakage protective requirement of power direction type; amplitude with this signal; judge with the same operation of zero-sequence current requirement by setting value; and the phase place of residual voltage and the phase place of zero-sequence current compared; when phase relation satisfies electric leakage feature and zero-sequence current; when the amplitude of residual voltage all reaches setting value, then make protective reaction.
Low-voltage, high-tension protection operation are described.When becoming 100V voltage behind the three-phase and five-pole transformer output 6000V; after the further step-down of the power transformer of comprehensive protector, carry out rectification (perhaps not rectification); this voltage signal is added to another signal input of variable connector; this voltage channel of gating under the central controller program control; voltage signal is delivered to the A/D converter; carry out the A/D conversion; read in by central controller then; carrying out digital quantity handles; weighted average etc. for example, subsequently, central controller is with magnitude of voltage and high voltage; the pre-tuning value of low-voltage compares; when magnitude of voltage during, by whether overvoltage operation of procedure identification greater than the high voltage standard value or less than the low-voltage standard value.If abnormal electrical power supply occurs, then start protection motion action program.If voltage is normal, then magnitude of voltage is delivered to voltage display driver unit demonstration voltage at that time.
The present invention protect the motion action program comprise output operate a switch signal, start memory program and finish accident record, start alert program and go to send alarm signal, start the troubleshooting communication program, contents such as error protection reason are delivered to communication interface or the like.
Fig. 4 is the operation principle block diagram of another embodiment of comprehensive protector of the present invention.In Fig. 4, the secondary singal that instrument transformer is answered after decaying by rectification circuit become direct current signal, again through filter filtering, in voltage comparator, signal level and setting value level are compared then, the output of comparator has only low level or high level two states, this level is directly delivered to a certain port of central controller (single-chip microcomputer), and central controller identification logical value is altogether judged.In this embodiment, setting value directly is provided with band switch or other similar parts (for example potentiometer), and is added on the normal end of comparator with the method for the electric resistance partial pressure current potential of will adjusting.
Fig. 5 is the schematic diagram that the central controller to comprehensive protector of the present invention shields.As shown in the figure, the box (1) of metal material being made square or rectangle covers on the central controller (2), and make can (1) ground connection, below in central controller (2), utilize the ground wire of the Copper Foil formation of printed board (3), so that play shielding action for the interfere with electromagnetic field under the coal mine greater than the area of central controller (2).
Fig. 6 is the schematic diagram to the monoblock wiring board shielding at the central controller place of comprehensive protector of the present invention; the method of this shielding is that the box (1) that metal material is made square or rectangle is covered on the monoblock wiring board (3) at central controller (2) place; so that play shielding action for the interfere with electromagnetic field under the coal mine equally, this wiring board (3) can be connected with lead by the aperture on the box (1) with connection between other circuit board (4).