Mining power compensating device
Technical field
The present invention relates to a kind of mining power compensating device, compensate performance and explosion insulation performance obtains the power compensating device of comprehensive improvement more particularly to a kind of
Background technology
Along with the total installation of generating capacity of coal industry mining machinery equipment and separate unit installed capacity be continuously increased and the low-pressure system of mining area periphery electric substation is in harsh environmental conditions, supply line is apart from the reason such as distant, cause supply line's loss big, average power factor is all very low, and the capacity of mining machinery equipment can not make full use of, therefore, a lot of mining areas start to consider to improve power factor to meet the compensation needs of mining machinery equipment.In prior art, the method taked is exactly directly install common reactive power compensation system in the electric substation in exploiting field to improve the power factor of mining machinery equipment, although this method can reach compensating power, improve the purpose of power factor, but the damps such as methane it are contained within due to mining area, very easily ignite damp when common reactive power compensation system work and accident of blasting, cause very big threat to the operating personnel under mine and mine.
Accordingly, because the load major part in Coal Mine Power Network is inductive load, electrical network is installed shnt capacitor and can supply the part reactive power that inductive reactance consumes.Shnt capacitor compensates simple economy, flexibly and easily.But current colliery also exists the equipment that a large amount of reactive power frequently changes, such as coal-winning machine, large-scale drag conveyor, pumping plant, elevating conveyor etc., the feature of these loads: power is big, starts frequent etc..This will ask compensation device can carry out dynamic compensation according to the change of load.And shnt capacitor can only compensate fixing idle, it is easy to caused benefit or owe mend, it is impossible to meet being actually needed of system, it is also possible to system generation parallel resonance, cause Harmonics amplification.Therefore, currently generally capacitor is grouped, utilizes microcomputer to be controlled, the change according to power factor, Capacitor banks is carried out automatic switching, to realize the automatic of reactive power is compensated.
The reactive power automatic compensation device used in underground coal mine low voltage electric network at present mainly has following defect: one is the fling-cut switch using A.C. contactor as capacitor; it major downside is that switching speed is slower; can not quickly follow the tracks of the change of load reactive power; and switched capacitor can cause more serious inrush current and switching overvoltage often; thus causing the contact of A.C. contactor to burn or compensating the internal breakdown of capacitor, have a strong impact on the service life of device self;Two is as detection limit and control target using power factor in control mode, owing to power factor sampling mode only detects the phase contrast of the voltage in electrical network and electric current, therefore can not accurately reflect the idle component size of load in electrical network, easily cause switching during underloading and shake thus affecting the service life of compensation device and the safe operation of electrical network and subscriber equipment.
Meanwhile, the load capacity such as the various RHVCs in underground coal mine low voltage electric network, commutator constantly increases.The application of a large amount of power electronic power devices and device, bring to mine while energy-conservation and energy conversion, also serious pollution is caused to supply network, substantial amounts of harmonic injection power system in mines, cause system effectiveness step-down and other equipment and device are produced disturbance, threatening the safe operation of power system in mines.For colliery low voltage electric network, owing to the structure of electric power system and the number of times of harmonic wave are substantially stationary, therefore it is generally adopted by the appropriately combined passive filter of filter capacitor, reactor and resistor to suppress harmonic wave.And current passive filter is generally adopted using A.C. contactor as fling-cut switch, come into operation with manual type is fixing, the major defect of this mode is the change that can not quickly follow the tracks of load, when producing the load excision of harmonic wave, wave filter can not excise in time, and more serious inrush current and switching overvoltage can be caused during with catalyst switching filters, thus causing the contact of A.C. contactor to burn or the internal breakdown of filter capacitor, have a strong impact on the service life of device self.
SVG can improve the power factor of Coal Mine Power Network, reduce the power consumption in conveying circuit, improve the load capacity of multi-line power transmission ability and transformator, administer harmonic wave, suppress voltage pulsation, thus reaching effect that is energy-saving and cost-reducing and that improve the quality of power supply, it is possible to obtain good economic benefit, have broad application prospects in Coal Mine Power Network.Therefore, in the last few years, SVG dynamic passive compensation and harmonic synthesis controlling device were subject to widely studied.
nullCN201120124248 discloses a kind of anti-explosive filter compensation energy-saving set device for mines,It includes controller and switching unit,Described switching unit includes three group capacitors,Every group capacitor is by three electric capacity C connections triangular in shape,The three-phase bus A of three electric connection points between electric capacity C and distribution system、B、Vacuum contactor it is serially connected with between C、Reactor、Isolation switch,Distribution system three-phase bus is provided with current transformer,It is provided with voltage transformer between reactor and vacuum contactor,The input of described controller respectively with current transformer、Voltage transformer electrically connects,The end that controls of described vacuum contactor electrically connects with the outfan of controller,Described controller obtains current and voltage signals by sampling current transformer and voltage transformer and processes,And control three group capacitor switchings by vacuum contactor.But, the collection of power distribution system current voltage signal is still suffered from delayed by this device, and energy-saving effect is not good enough.
CN200920280642 discloses a kind of mining automatic reactive power compensation, it is made up of housing parts and electric part, electric part is installed in housing parts, electric part is by isolating switch, reactive power compensating controller, Programmable Logic Controller, vacuum contact is cried, protection fuse, Capacitor banks, Reactor banks, current transformer, control transformator to constitute, wherein the housing of mining automatic reactive power compensation adopts double swing doors, left front door and right front door are respectively designed with observation window, the door inwall at observation window rear has been respectively fixedly connected with factor display, the screen position of factor display is corresponding with observation window.The autocompensation installation of said structure can show more parameter than legacy equipment, but it is not high to compensate sensitivity.
Accordingly, it would be desirable to a kind of compensate highly sensitive, efficiency is high, saves energy and reduce system loss mining dynamic compensating device.
Summary of the invention
For the above-mentioned problems in the prior art, the present inventor is through further investigation, it is provided that a kind of mining power compensating device and control method thereof.
On the one hand, provide a kind of mining power compensating device, it can include electric part and flame proof and construction for heat radiating device part, it is characterised in that described electric part includes SVG, fixed capacity (FC), chain H bridge power cell, device access switch, capacitance compensation branch road and control unit;
Described SVG can be made up of linked reactor, inverter and direct current capacitors, and every circuitry phase carries out cascade by the unsteady flow module that two rated voltages are 3000V, is directly accessed 3300V electrical network then through linked reactor;Wherein said inverter includes power switch tube S 1, power switch tube S 2, power switch tube S 3, power switch tube S 4, power switch tube S 5, power switch tube S 6, filter inductance L1 and filter inductance L2, and the colelctor electrode of power switch tube S 1 is connected with the positive pole of direct current DC after being connected with the colelctor electrode of power switch tube S 3 again;The negative electrode of power diode D1 divides three tunnels to be connected with the emitter stage of power switch tube S 1, the colelctor electrode of power switch tube S 5 and one end of filter inductance L1 respectively, the other end of filter inductance L1 is connected with one end of filter capacitor C, and the anode of power diode D1 divides two-way to be connected with the colelctor electrode of the emitter stage of power switch tube S 6 and power switch tube S 4 respectively;The negative electrode of power diode D2 divides three tunnels to be connected with the emitter stage of power switch tube S 3, the colelctor electrode of power switch tube S 6 and one end of filter inductance L2 respectively, the other end of filter inductance L2 is connected with the other end of filter capacitor C, and the anode of power diode D2 divides two-way to be connected with the colelctor electrode of the emitter stage of power switch tube S 5 and power switch tube S 2 respectively;The emitter stage of power switch tube S 2 is connected with the negative pole of direct current DC after being connected with the emitter stage of power switch tube S 4.
In above-mentioned inverter design, power switch tube S 5 constitutes alternating current bypass with power diode D2 and power switch tube S 6 with power diode D1, can effectively reduce common mode leakage current.Additionally, when HF switch pipe turns off, power switch tube S 5 constitutes alternating current bypass with power diode D2 or power switch tube S 6 with power diode D1, the voltage that DC is negative is 0.5Vdc by filter inductance input side, and during bipolar modulation, DC negative voltage is Vdc by filter inductance input side, so the harmonic wave of output electric current is less.Owing to adopting unipolarity modulation system, what decrease power switch pipe opens number, so conversion efficiency is higher, and is capable of reactive-load compensation.
Described fixed capacity (FC) can be made up of fixed compensation capacitor device and connection reactor.
The bridge circuit fully connecting structure that the structure of described chain H bridge power cell can be made up of IGBT.
Described control unit can mainly include master control cabinet, programmable logic controller (PLC) and touch screen.
Described flame proof and construction for heat radiating device part can be made up of the casing (i.e. power unit box) of the casing (i.e. starter box) of reactive-load compensation and active filter flame-proof mine reactor, mine flameproof and intrinsic safety type reactive-load compensation and active filter, the casing (i.e. reactor box) of Electric capacity compensation device flame-proof mine reactor and the casing (i.e. capacitor box) of Electric capacity compensation device flame-proof mine capacitor.
In above-mentioned flame proof and construction for heat radiating device part, starter box and power unit box are the first branch road, reactor box and capacitor box is the second branch road, accesses in electrical network after this two branch circuit parallel connection.
The loop of fixed capacity (FC) can be mainly made up of Large Copacity high-voltage capacitor, current-limiting reactor, machinery switching device, for providing capacitive reactive power to system and filtering a number of harmonic wave.
Capacitance compensation branch road can provide to the compensation ability of SVG and supplement.
The pondage of the power compensating device of the present invention is at perception 5000kvar to capacitive 5000kvar continuously adjustabe.
In a preferred embodiment, in the flame proof of the present invention and construction for heat radiating device part, casing is the design of Flameproof intrinsically safe three chamber, main chamber and wire connection cavity are rectangular structure, heat-pipe radiator is installed in main chamber, the substrate of heat-pipe radiator is installed the components and parts such as IGBT power component, electric capacity, heat sensor, main cavity adopts bolt fastening structure with door closure, wire connection cavity is provided with cable entry, externally connected by cable entry, casing is additionally provided with heat-pipe radiator and radiator cover, and installs lower two flame-proof mine ventilation blowers, to strengthen heat radiation.
The capacitor of capacitance compensation branch road can be under high vacuum condition on polypropylene screen sprayed metal layer, then roll, impregnate then through fine vacuum after drain, load the element being sealed to form in plastic casing, with thermosetting resin,.Owing to polypropylene screen has good ageing resistance, it is extremely low that capacitor has self-healing property, loss and temperature rise, and therefore this capacitor has very long life-span and significantly high reliability.In the present invention, by using described capacitor, instead of frangible porcelain bushing shell with firm lead-in wire, it is to avoid contingent damage during installation.Additionally, each unit of capacitor is respectively arranged with discharge resistance, when capacitor is from after disconnecting power supply, voltage between capacitor pole being made within very short time to be down to below safety value.
On the other hand, present invention also offers the control method of mining power compensating device mentioned above, it includes making SVG first pass through charging resistor and DC bus capacitor is charged, after DC capacitor voltage reaches predetermined value, short circuit contactor closes, charging process terminates, SVG starts working, the master controller of the SVG voltage by acquisition system bus bar side, current signal, calculate the harmonic current or reactive current that need to compensate, last controller generates the driving signal needed for inverter, control inverter and produce and the compensation electric current of opposite in phase equal with load harmonic current or reactive current amplitude, thus realizing filtering the purpose of harmonic wave or compensating reactive power.
The control method of described SVG is preferably Current Indirect Control method, the output voltage of inverter and grid side voltage in phase, and device does not consume active power.
Preferably, by used in parallel to described mining power compensating device and high-voltage capacitance compensation device, the Reactive-power control of the silent oscillation passive dynamic passive compensation complete device that two parts parallel connection is constituted ranges for 0~10000kvar.
The power compensating device of the present invention is in colliery uses on the spot, when load motor starts, voltage can be brought up to 2.81kV by original 2.50kV, electric current is dropped to 120A by 161A, the time of current break is shortened to 1.8s by original about 4.6s, start overall process and shortened to about 30s by about 45s, when load motor runs, power factor is risen to 0.97 by 0.77, and reactive power is dropped to 19kvar by 208kvar, and harmonic current is dropped to 29A by 40A.Thus substantially can be seen that, voltage drop effectively obtains suppression, and starting current reduces, and the startup time also substantially shortens, additionally network system voltage stabilization operationally, accident rate declines, and Homes Using TV improves, correspondingly accident treatment time decreased, the normal production time increases, it is achieved thereby that minimizing accident, increase production and improve productivity, reduce the purpose of investment cost.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of the flame proof of the present invention and construction for heat radiating device part.
Fig. 2 is the circuit structure diagram of the inverter of the present invention.
In FIG, description of reference numerals is as follows: 1-starter box, 2-power unit box, 3-reactor box, 4-capacitor box, 5-power distribution equipment, 6-load motor.
Detailed description of the invention
Below in conjunction with accompanying drawing, the present invention is expanded on further, but the present invention is not limited to described accompanying drawing.
Embodiment 1: flame proof and construction for heat radiating device
With reference to Fig. 1, described flame proof and construction for heat radiating device mainly include starter box (1), power unit box (2), reactor box (3) and (4) four parts of capacitor box, described casing is connected with load motor (6) by power distribution equipment (5), and starter box (1) and reactor box (3) are in parallel.
Embodiment 2: the circuit structure of inverter
With reference to Fig. 2, the circuit structure of inverter includes: power switch tube S 1, power switch tube S 2, power switch tube S 3, power switch tube S 4, power switch tube S 5, power switch tube S 6, filter inductance L1 and filter inductance L2.The colelctor electrode of power switch tube S 1 is connected with the positive pole of direct current DC after being connected with the colelctor electrode of power switch tube S 3;The negative electrode of power diode D1 divides three tunnels to be connected with the emitter stage of power switch tube S 1, the colelctor electrode of power switch tube S 5 and one end of filter inductance L1 respectively, the other end of filter inductance L1 is connected with one end of filter capacitor C, and the anode of power diode D1 divides two-way to be connected with the colelctor electrode of the emitter stage of power switch tube S 6 and power switch tube S 4 respectively;The negative electrode of power diode D2 divides three tunnels to be connected with the emitter stage of power switch tube S 3, the colelctor electrode of power switch tube S 6 and one end of filter inductance L2 respectively, the other end of filter inductance L2 is connected with the other end of filter capacitor C, and the anode of power diode D2 divides two-way to be connected with the colelctor electrode of the emitter stage of power switch tube S 5 and power switch tube S 2 respectively;The emitter stage of power switch tube S 2 is connected with the negative pole of direct current DC after being connected with the emitter stage of power switch tube S 4.
The open present invention of this written description use-case, including optimal mode, and also enables those skilled in the art manufacture and use the present invention.The present invention can the scope of granted patent be defined by the claims, and can include other example that those skilled in the art expect.If other example this has the structural element of the literal language not differing from claims, if or other example this includes the equivalent structure element without substantial differences of the literal language with claims, then other example this intention is within the scope of claims.Under not resulting in inconsistent degree, by reference by herein with reference to all references part be incorporated herein.