CN1066345A - The reactive power compensation that single-chip microcomputer is controlled automatically and the integration unit of relaying protection - Google Patents

Abstract

The invention belongs to a kind of circuit arrangement of power supply-distribution system.Low, the baroque problem spy of reactive power compensator efficient provides this programme in the prior art in order to overcome, this scheme adopts single chip microcomputer to do center control, adopt the operation principle of two closed loops, did the coarse adjustment of mending to select the suitable capacitor panel of switching, and make the static real-Time Compensation that fine setting realizes the loaded line High Power Factor with thyristor controlled reactor, it has cos φ can keep being stabilized in 0.999 the advantage that height value, dynamic response are fast, reliability is high, antijamming capability is strong.

Description

The reactive power compensation that single-chip microcomputer is controlled automatically and the integration unit of relaying protection

The invention belongs to a kind of circuit arrangement of power supply or distribution, it relates to the method and apparatus of novel reactive power compensation, also comprises the device of relaying protection.

To carry out dynamic reactive power compensation be energy-conservation and the important means of improving power supply quality to electrical network or power equipment, China's very low present situation of present energy deficiency power supply capacity is seen, improving power factor is the energy-conservation important method of fully taping the latent power, and epochmaking realistic meaning is arranged.Research and design reactive power compensating apparatus all in various countries' industrial development process, make every effort to improve effective application to electric power, in recent years along with the development of computer give seek a kind of simple in structure, automatic stabilisation, efficient is high and lower-cost compensation equipment provides the new world.Traditional electric network reactive-load control device is divided into rotation compensator and silent oscillation capacitor compensation two big classes.Existing silent oscillation reactive power compensation device generally adopts the input and the excision of power factor mode or reactive power mode control compensation electric capacity.Retrieval according to Patent Office of the People's Republic of China has proposed relevant close patent: 1. US4188573 " the static reactive power generator with time correlation error concealment device ", be to provide appropriate reactive power identical with voltage in this patent with the electric current that keeps power supply with each alternate electric capacity and thyristor controlled inductance, reduce the voltage fluctuation of circuit, for the accuracy of the reactive power that is provided is provided, be provided with the controllable silicon correlated error arrester of the duration of ignition at device interior, and proposed the implementing method of three kinds of these arresters; 2. US3936727 " being used for the stable reactive power High-speed Control of voltage in electric power system ": the reactive power generator that this patent provides is made up of the inductance of one group of fixing electric capacity and the reverse-blocking tetrode thyristor control in parallel with load, its control is to draw the controllable silicon conduction angle according to different between the angle of the angle of load current and critical busbar voltage and line current and critical busbar voltage through add operation, make phase shifting control, basically the reactive component with load current is equal and opposite to keep the reactive power compensation electric current, and relates to the continuous high speed control of reactive power.The common feature of preceding two patents is that they all are to adopt one group of fixing capacitor.Be to adapt to the fluctuation of bigger reactive load, it is big that capacitor volume is wanted, and the capacity of its inductance also will strengthen thereupon, equipment cost height not only, and its power loss also strengthens; 3. CN87100007 " single chip microprocessor wattless power controller ": it has proposed that accurate Calculation is selected to drop into or excision capacitors count and judge at dropping into district, excision district, the four kinds of information summaries in wave zone and stable region, determine the capacitor of reasonable switching, to eliminate the method for " vibration " phenomenon.But the reactive power compensation of this patent is the adjusting that level is arranged, and the response time is long, and control precision is very low under underload.As seen still lack comparatively ideal reactive power compensating apparatus at present, so that power factor energy stable regulation is to higher level.

The objective of the invention is provides a kind of reactive power silent oscillation dynamic compensation of control fully automatically and the integration unit of relaying protection for solving the above problems to power network, regional transformer station, enterprise, rural area electric substation, power circuit and large and medium-sized power equipment; it can make cos ∮ reach 0.999 or arbitrary required value, and it has the advantages that dynamic response is fast, reliability is high, antijamming capability is strong, adaptability is good.

By as above design, the feature of " single-chip microcomputer is the method for the reactive power compensation of control automatically " of the present invention is: it is controlled at the coarse adjustment of selecting switching to cross benefit do reactive power compensation in a plurality of capacitor panels automatically with single-chip microcomputer Direct Digital formula, and do fine setting by the little reactor of capacity of SCR control and realize High Power Factor numerical value on the loaded line as 0.999 or the dynamic real-time compensation of arbitrary value, the control procedure of its single-chip microcomputer is to adopt two closed-loop digital PID adjusters to realize.Totally four groups of its capacitor panels wherein have a capacity less, and its switching mode is by the software control switching cycle.Two closed loops are by encircling in the inductive current by the PID design of Regulator and being constituted by total reactive current outer shroud of PID design of Regulator.

The feature of " integration unit of compensation and relaying protection automatically " provided by the present invention is: it has adopted the principle of two closed loops; adopted novel phase angle detection circuit; adopted antijamming capability strong linear photoconductor isolated amplifier and photoelectric isolated driver, the circuit of this equipment is by the major loop three-phase current detection circuit; the major loop phase angle detection circuit; the testing circuit of each load circuit electric current and voltage; linear isolation amplifier; analog to digital converter; centralized control unit CPU comprises that also numeral shows; keyboard; printer; the single chip microcomputer part of memory under program; photoelectricity is isolated the reactor part that triggers the controllable silicon driving; the capacitor box of photoelectricity isolation drive reaches partly that the under-voltage and current foldback circuit by executive component is constituted with the auxiliary relay.Its novel main circuit phase angle detection circuit is that the zero-crossing comparator by voltage and current connects not gate and constituted, and signal is input to the external interrupt request incoming line INT of single-chip microcomputer separately then ₀And INT ₁Its linear photoconductor isolated amplifier is made up of two photoelectrical couplers and two operational amplifiers, and it is a not linear amplifier on ground altogether.Its digital photoelectric isolated driver is made up of photoelectrical coupler and bidirectional triode thyristor.Totally four groups of its capacitor panels.The capacity Q of its reactor _L=(1.3～2) Qc max.

Adopt the superiority of this programme below embodying: 1. to rise to 0.999 energy-saving effect by original 0.7～0.8 remarkable for power factor, reduced the active loss in the power circuit, can reduce the loss 10～20% of electric energy; 2. the voltage fluctuation that can avoid bigger reactive power to flow and caused in electrical network improves power supply quality; 3. also can accomplish the flickering that suppresses voltage; 4. improved the utilance of generator, transformer, circuit and controller switching equipment, with 90 years national generating capacity 6,000 hundred million degree was example, because cos ∮ brings up to 0.999 level, can increase the supply of electric power of nearly 96,000,000,000 degree every year, be equivalent to increase by 36 and overlapped 300,000 kilowatts generating set; 5. flexibility is strong adapts to widely, can be used for electrical network, and regional transformer, also can be used on big-and-middle-sized electric equipment at enterprise, can reach obviously energy-conservation and don't strengthen the effect of investment.6. make enterprise's energy increase-volume 10～30% under the situation of not changing transformer.

Operation principle below in conjunction with description of drawings this programme main embodiment.Fig. 1 is the main circuit schematic diagram.(1) among the figure, (2), (3) are four different group capacitor cabinets of capacity.(4) be the little reactor of capacity, (5) reverse-blocking tetrode thyristor, (6) air switch.Is exactly the reactor part of controlling by reverse-blocking tetrode thyristor in the frame of broken lines, it and capacitor panel is supporting is installed on the transformer low voltage bus.

This device is to do coarse adjustment with automatic classification switched capacitor cabinet, does fine setting with reactor and realizes providing the reactive power that compensates usefulness accurately.Electric load mostly is perception, and at any time becoming, establishes load or burden without work Q ' shown in Fig. 2 curve.Fig. 2 is the schematic diagram of reactive power compensation situation.COMPUTER DETECTION electric current in the main circuit be perception and with given power factor value not simultaneously, send the order that drops into capacitor panel immediately, till capacity current occurring, drop into 2 capacitor panels 0 the time as figure, overcompensation appears this moment, computer digit PID adjuster sends instructions and regulates reactor current immediately to keep cos ∮ 〉=0.999(or arbitrary setting), at o～t ₁Only needing to change inductive current in stage finely tunes.Qc _∑Required whole capacitor volume during for full compensation, Qc ₁, Qc ₂, Qc ₃Capacity for the single capacitor cabinet.

Fig. 3 is the theory diagram of complete machine.The control device of reactive power compensation is to be the synthetic circuit of core with the single-chip microcomputer, it has comprised the double-loop circuit with the outer shroud of the interior ring of control inductive current and control reactive current, it has all advantages of double loop system, and, antijamming capability fast as precision height, governing speed is strong or the like.The adjusting of two rings and silicon controlled numeral trigger to be finished by single-chip microcomputer.

Fig. 4 is the circuit theory diagrams of complete machine.Fig. 5 is the block diagram of main program.

Fig. 6 is an electrical block diagram novel in the phase detecting circuit of main circuit.It is by two cover zero-crossing comparator B ₁, B ₂With not gate F ₁, F ₂Form.Its feature is an accuracy of detection height, simple, reliable.Antijamming capability is strong.In addition, main circuit current feedback, inductor current feedback amount are all passed through high performance linear photoconductor isolated amplifier, realized effective isolation of strong power system and computer system, both guaranteed the linear relationship between feedback signal and the measured signal, overcome the harmful effect of various interference signals to system again effectively, there is extremely strong interference free performance in the system that guaranteed.Fig. 7 is the structure chart of linear photoconductor isolated amplifier.It is by two photoelectrical coupler GD ₁, GD ₂With two amplifier A ₁, A ₂Constitute.

Fig. 8 is the structure chart that the switch of controllable silicon phase shifting control and capacitance switch is controlled the photoelectric isolated driver of usefulness, driver and clever sensitive relay that it can replace conventional pulse transformer to constitute, and it is by not gate F ₃, photoelectrical coupler GD ₃Reach bidirectional triode thyristor SCR and constitute, both realized the isolation of strong power system and computer system, also reduced volume, improve antijamming capability, guarantee to trigger reliably, can save the time of CPU again greatly.

In this programme for making a capacitor panel not make switching for the second time at short notice, employing is solved by the method for computer software " queuing ", because designed reactor capacity is greater than the capacity of a capacitor panel, in the ordinary course of things, the repeatedly switching of capacitor panel in the time of can avoiding load change.Promptly so-called " vibration " phenomenon frequent switching can appear, in beating just when the critical numerical value of a capacitor panel of switching of short-term operation load (as electric welding machine) repeatedly but at some in particular cases.Fig. 9 is a frequent switching situation schematic diagram.Can take three kinds of measures for overcoming this problem: 1. the reactor capacity is big than a capacitor panel capacity, but Q _L=(1.3～2) Qc max; 2. the capacity of capacitor panel does not wait, and has a capacity less; 3. solve " queuing " problem with software, accomplish switching cycle, can solve above-mentioned " vibration " problem.Figure 10 avoids the compensation situation schematic diagram that vibrates.

This device when the main circuit load is lower than the load limit value of not controlling of a regulation, now is defined as 2% of rated load during on-line operation, and can be in wait state this moment, when be higher than rated load 5% the time can put into operation immediately.Can realize unattended like this, be applicable to that the unit of various dutys uses, and the controllable burden scope be big, is better than other scheme of prior art.

This device also has decompression, the phase failure, the overload of main circuit, the function of overcurrent protection; its every work is finished by the software of computer; through calculating and the judgement to various information value, it can send the switch that shows alarm or cut off main circuit by its executive component auxiliary relay work.

Another embodiment of this programme: for middle and small transformer substations, require in power factor under the situation of not too high, no big frequent fluctuation load, for reducing investment, can cancel the controllable silicon reactor part in the dotted line among Fig. 4, directly adopt the method for computer switched capacitor cabinet to come compensation adjustment.When the numerical value of measuring main circuit current I1 and power factor cos ∮, calculate active current and reactive current, and compare with the reactive current of the corresponding permission that calculates, if overseas, then calculate and determine and should throw the capacitor panel of (cutting) at permissible value.Actual measurement cos ∮ value behind the switching compares with permissible value as calculated, can remake first and second and adjust and can put in place.In addition, for frequent switching capacitor not when the electric motor starting, in software, taked to exceed continuously overseas 20 seconds (this value is adjustable) after, could do the operation of switching.

Adopt this programme will obtain great economic effect; The annual loss that reactive current forms on circuit and each electric equipment is huge, only with regard to the statistics in 85 years in Shanghai, the reactive power compensation capacity of user's set is 226.1 ten thousand kilovars, remove outside user's the capacity of autocompensation installation, also have 550,000 kilovars reactive power in electrical network, to flow, be equivalent to annual waste 2,000 ten thousand degree electric energy.The model machine of this programme is respond well certain factory operation on probation 1 year, and power factor can stably remain on 0.999, and run duration is amounted to and saved 60,000 degree.An its capacitor box capacity is 56KVAr, and minimum capacitor panel capacity is 48KVAr.The capacity of reactor is 80KVA.

Claims (8)

1, a kind of reactive-load compensation method of controlling automatically with single-chip microcomputer, it is characterized in that using single-chip microcomputer Direct Digital formula to be controlled at the coarse adjustment of selecting switching to cross benefit do reactive power compensation in a plurality of capacitor panels automatically, with be not more than reactor by capacity of SCR control and finely tune, realize inductive load circuit High Power Factor numerical value, as 0.999 or the compensation of the dynamic real-time of arbitrary value; The control procedure of its single-chip microcomputer adopts two closed-loop digital PID adjusters to realize.

2, according to the described reactive-load compensation method of claim 1, it is characterized in that capacitor panel adopts four groups, wherein there is a capacity less, its switching mode is by the software control switching cycle.

3, according to the described reactive-load compensation method of claim 1, the two closed loop numerical controls that it is characterized in that it are by being constituted by the interior ring of the inductive current ring of PID design of Regulator with by the outer shroud of total reactive current ring of PID design of Regulator.

4; a kind of with the reactive power compensation of the automatic control of single-chip microcomputer and the integration unit of relaying protection; it is characterized in that it has adopted the structure of two closed loops; adopted novel phase detecting circuit; adopted the optical isolation amplifier and the digital photoelectric isolated driver of the strong linearity of antijamming capability, the circuit of this device is by the major loop three-phase current detection circuit; the major loop phase angle detection circuit; each load circuit voltage and current detection circuit; linear isolation amplifier; analog to digital converter; master controller CPU comprises that also LED shows; keyboard; printer; the single chip microcomputer part of memory under program; photoelectricity is isolated the reactor part that triggers the controllable silicon driving; it is that the under-voltage current foldback circuit of executive component is formed that the contactor capacitor panel of photoelectricity isolation drive partly reaches with the auxiliary relay.

5, according to the integration unit of described reactive power compensation of claim 4 and relaying protection, the main circuit phase angle detection circuit that it is characterized in that it is to be input to single chip microcomputer external interrupt request incoming line INT with two zero-crossing comparators through not gate ₀, INT ₁Form.

6, according to the integration unit of described reactive power compensation of claim 4 and relaying protection, it is characterized in that its linear photoconductor isolated amplifier is made up of two photoelectrical couplers and two operational amplifiers, it is a not linear amplifier on ground altogether.

7,, it is characterized in that its digital photoelectric isolated driver is made up of photoelectrical coupler and bidirectional triode thyristor according to the integration unit of described reactive power compensation of claim 4 and relaying protection.

8,, it is characterized in that the capacity Q of its reactor according to the integration unit of described reactive power compensation of claim 4 and relaying protection _L=(1.3～2) Qc max.

Images