CN205407281U - Three phase load automatic regulating apparatus of distribution network - Google Patents
Three phase load automatic regulating apparatus of distribution network Download PDFInfo
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- CN205407281U CN205407281U CN201620271441.XU CN201620271441U CN205407281U CN 205407281 U CN205407281 U CN 205407281U CN 201620271441 U CN201620271441 U CN 201620271441U CN 205407281 U CN205407281 U CN 205407281U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
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Abstract
The utility model discloses a three phase load automatic regulating apparatus of distribution network, include unbalanced three phase conditioning controller, switch return circuit and the space compensation unit and the alternate compensation unit that control by the unbalanced three phase conditioning controller, space compensation unit can be according to the size of distribution transformer capacity and is set up the branch road scalar sum capacity in the unit, and alternate compensation unit can be according to the size of the idle volume of distribution transformer and is set up the branch road scalar sum capacity in the unit. The unbalanced three phase conditioning controller is automatic calculation distribution network three phase line's active power and reactive power on line, according to imbalance degree's size, selects suitable space compensation capacity and alternate compensation capacity, controls the automatic switching of blend switch then, and each compensates mutually to the distribution network, guarantees the load balancing between each looks circuit of distribution network. The utility model has the advantages of simple structure, simple to operate, commonality are strong, the during operation temperature rise is low, and loss and noise are all very low.
Description
Technical field
This utility model relates to a kind of power distribution network three-phase load self-checking device, it is adaptable in low-voltage power supply system, three-phase imbalance load is administered, and belongs to power technology and electronic technology field.
Background technology
In power system, consuming of electric energy mainly relies on distribution to realize, and especially relies on power distribution network low pressure to realize.China's low voltage electric load typically refers to the load that alternating current 220V/380V system is with.Alternating current 220V/380V system is generally made up of three-phase and four-line, namely A phase, B phase, C phase, N phase.Power distribution network low-voltage electric energy is dependent on the cable run of certain distance or wire line conveying and distribution, and the inductance in low-voltage circuit is inevitable.Thus, the reactive power in load is also just implicitly present in.The load that power distribution network low-pressure side is with comprises single-phase and three-phase load, and for threephase motor, time properly functioning, three-phase load is in poised state, is nearly all single-phase load for residential electricity consumption, makes power distribution network be in absolutely not poised state.In addition, owing to resident load is usually drawn from step down side with cable or wire, it is difficult to during installation control transformator output load partition equilibrium.Although when being install, three-phase load distribution is balanced, but due to the seasonality of electricity consumption, period and different time rates, the imbalance of three-phase load is absolute existence.Fact proved, local at some, three-phase imbalance rate is up to more than 80%, it may be said that low-voltage power system three-phase load absolute equilibrium is perfect condition, and imbalance is normality.
The imbalance of three-phase load, to power system bring first greatly harm be the increase of line loss.Square being directly proportional of numerical value and the electric current that line loss increases.Assume that certain three-phase line or transformer resistance are equal and equal to R, if three-phase load is balance, its loss △ P=I2R, and △ Pa=△ Pb=△ Pc.Three-phase total losses ∑ △ P=3I2R.When system is in unbalanced state, it is assumed that A phase load is zero, and B, C biphase mean allocation A phase current, then system loss △ Pa=0, △ Pb=△ Pc=(1.5I) 2R=2.25I2R, then circuit total losses ∑ △ P=4.5I2R, line loss increase amount is 4.5I2R-3I2R=1.5I2R, namely total line loss adds 50%.Easily release, if three-phase load is provided by a phase, ∑ △ P=(3I) 2R=9I now2R, then line loss increase amount is 9I2R-3I2R=6I2R, namely total line loss adds 200%.The circuit being in operation often is burned with anger because certain phase crosses stream, and operating transformator can because the heating leakage of oil of low pressure phase overcurrent or wiring pile close and burn out.For power department, add breakdown repair number of times and O&M cost, reduce power supply reliability.
The imbalance of three-phase load, the second largest harm brought to power system is that transformer iron core loss increases.Distribution transformer many employings three-iron core column structure of Y/Y0 or △/Y0 wiring, when there is three-phase current unbalance, primary side non-zero-sequence current exists, and secondary side has zero-sequence current to exist, this electric current is that pure exciting current produces zero sequence fluxes, because this magnetic flux does not have closed magnetic circuit, need to be closed by fuel tank tank wall, thus heating produces loss in iron core, fuel tank and conductive magnet accessories.
The imbalance of three-phase load, the third-largest harm brought to power system is to produce variation, can cause the imbalance of three-phase voltage, affect the even motor damage of exerting oneself of threephase motor time serious.
Currently, power department solves the way of three-phase imbalance, and Load adjustment is removed at residential electricity consumption scene of mainly often dispatching officers.But the imbalance of three-phase load is a kind of dynamic process, has its seasonality, period, at any time all in change, manually the way of Load adjustment can only solve temporary problem, and must not solve root problem, and time-consuming, take a lot of work, produce little effect.
In addition with common benefit and point compensating method to three-phase imbalance load adjustment, the problem solving three-phase imbalance.Traditional common compensating method is the electric capacity accessing equivalent between three-phase system line, but the method throws away existing defects, it is assumed that transformer low voltage output voltage amplitude is equal, phase 120 °.Namely there is UA=U ∠ 0 °, UB=U ∠-120 °, UC=U ∠ 120 °；The watt current of each phase is Iar=U/Ra ∠ 0 °, Ibr=U/Rb ∠-120 °, Icr=U/Rc ∠ 120 °.After accessing equivalent electric capacity, each phase capacitive reactance is Xa=Xb=Xc=X ∠-90 °；Then each phase capacitance current respectively 0 °/X of Iaq=U ∠ ∠, 90 °=U/X ∠ 90 °；Ibq=U∠-120°/X∠90°=U/X∠30°；Icq=U∠120°/X∠90°=U/X∠210°.After access electric capacity, the electric current of each phase is Ia=Iar+Iaq=Iar+U/X ∠ 90 °；Ib=Ibr+Ibq=Ibr+U/X∠-30°；Ic=Icr+Icq=Icr+U/X∠210°.From above formula it can be seen that after access benefit electric capacity altogether, because the U/X numerical value of each phase is equal, the electric current of each phase numerically variable quantity is also equal, so the effect of balanced load can not be played, can only change certain angle on vector.Traditional point of compensating method is that the capacitance current in certain phase is vertical with the watt current in this phase at the different electric capacity of the alternate access of three-phase system, and capacitance current is projected as zero in watt current, so watt current and active power can not be changed.
Therefore, for the deficiencies in the prior art, working out a kind of power distribution network three-phase load self-checking device is technical task highly significant.
Summary of the invention
The purpose of this utility model is to solve the problems referred to above that prior art exists, thus providing a kind of power distribution network three-phase load self-checking device, automatically adjusts power distribution network three-phase load, it is ensured that the three-phrase burden balance of power distribution network.
nullTechnical solution of the present utility model is: a kind of power distribution network three-phase load self-checking device，It is installed in three-phase circuit system，It is characterized in that: include three-phase imbalance regulable control device、Compensating unit and alternate compensating unit between switching circuitry and the line that controlled by three-phase imbalance regulable control device，Between described line, compensating unit and alternate compensating unit are equipped with multiple compensation capacitance group according to the size of capacity，Each compensation capacitance group includes three single phase compensation capacitors，The A phase of described three-phase imbalance regulable control device and power distribution network、B phase is connected with C，Between described line, compensating unit compensates one end of three single phase compensation capacitors in capacitance group through switching circuitry respectively with the A phase of power distribution network、B phase is connected with C，The other end respectively with the B phase of power distribution network、C phase is connected with A phase，Described alternate compensating unit compensates three single phase compensation capacitor one end of capacitance group through switching circuitry respectively with the A phase of power distribution network、B phase is connected with C，The other end is all connected with the N line of power distribution network.
Further, above-mentioned power distribution network three-phase load self-checking device, wherein: described switching circuitry includes phase three-wire three combination switch and miniature circuit breaker, phase three-wire three combination switch compensates capacitance group with each and is connected, and miniature circuit breaker is connected between each phase of power distribution network and phase three-wire three combination switch.
Prominent the having the technical effect that of this utility model: this utility model size according to distribution transformer capacity, select compensating unit and alternate compensating unit between the line of phase suitable capacity, and power distribution network is respectively compensated by mutually, it is ensured that the alternate balancing the load between each phase of power distribution network；And, power distribution network three-phase imbalance described in the utility model regulates device and has the feature of versatility, without understanding load character and degree of unbalancedness during the installation of device, when not changing existing support structures, determine the capacity regulating device according to the capacity of transformator；In addition, the three-phase and four-line of device is connected after installing by device described in the utility model with the outfan of distribution transformer, and accessing corresponding current signal, three-phase imbalance regulable control device calculates active power and the reactive power of three-phase automatically, the size automatic switching according to degree of unbalancedness and reactive power, select compensating unit and alternate compensating unit between suitable line, having simple in construction, easy for installation, during work, temperature rise is low, loss is low, noiseless feature.
Accompanying drawing explanation
Fig. 1 is that this utility model power distribution network three-phase imbalance regulates schematic diagram of device；
Fig. 2 is access capacitance current vectogram between A phase with B phase；
Fig. 3 is reactive power angle vectogram between A phase with B phase；
Fig. 4 is the FB(flow block) that power distribution network three-phase imbalance regulates apparatus control method.
In figure, the implication of each accompanying drawing labelling is: 1 three-phase imbalance regulable control device, compensating unit between 2 lines, 3 alternate compensating units, 4 switching circuitry, 41 miniature circuit breakers, 42 phase three-wire three combination switches.
Detailed description of the invention
Below by way of accompanying drawing in conjunction with detailed description of the invention, this utility model is described in further details.
As shown in Figure 1, this utility model power distribution network three-phase load self-checking device, it is installed in three-phase circuit system, including three-phase imbalance regulable control device 1, compensating unit 2 and alternate compensating unit 3 between switching circuitry 4 and the line that controlled by three-phase imbalance regulable control device 1, between described line, compensating unit 2 and alternate compensating unit 3 are equipped with multiple compensation capacitance group according to the size of capacity, each compensation capacitance group includes three single phase compensation capacitors, the A phase of described three-phase imbalance regulable control device 1 and power distribution network, B phase is connected with C, between line, compensating unit 2 compensates one end of three single phase compensation capacitors in capacitance group through switching circuitry respectively with the A phase of power distribution network, B phase is connected with C, the other end respectively with the B phase of power distribution network, C phase is connected with A phase.Three the single phase compensation capacitor one end compensating capacitance group in alternate compensating unit 3 are connected with the A phase of power distribution network, B phase and C respectively through switching circuitry, and the other end is all connected with the N line of power distribution network.
Further, described switching circuitry 4 includes phase three-wire three combination switch and miniature circuit breaker, and phase three-wire three combination switch compensates capacitance group with each and is connected, and miniature circuit breaker is connected between each phase of power distribution network and phase three-wire three combination switch, plays the effect of overcurrent protection.
The control method that this utility model belongs to power distribution network three-phase load self-checking device is as follows, as shown in Figure 4:
Each phase current Ia, Ib, Ic of three-phase imbalance regulable control device Real-time Collection distribution transformer；Each phase voltage Ua, Ub, Uc；Each phase active-power P a, Pb, Pc；Each phase reactive power Q a, Qb, Qc；Each phase power factor PFa, PFb, PFc；
(1) three-phase imbalance regulable control device judges the size of three phases active power Pa, Pb, Pc, take out Pmax and Pmin, degree of unbalancedness is calculated according to Pun=[(Pmax-Pmin)/Pmax] * 100%, as Pun >=K, start compensating unit between line, in formula: Pmax is maximum phase power in three phase power, Pmin is minimum phase power in three phase power, Pun is the three-phase power imbalance degree calculated in real time, and K is the limit value that unbalance control device sets, and span is between 0-1；
(2) as shown in Figure 3, three-phase imbalance regulable control device is by A, B phase active-power P a, Pb of recording and reactive power Q a, Qb, then can calculate A phase and B phase reactive power included angle a, φ b respectively, because A phase active power is Pa ∠ 0 °, B phase active power is Pb ∠-120 °, so, the diagonal angle on Qab limit is ab=120 ° of+φ b-φ a of φ, passes throughCalculate reactive power Q ab between the line between A phase and B phase, in like manner can calculate between the line between B phase and C phase reactive power Q ca between the line between reactive power Q bc, C phase and A phase；
(3) three-phase imbalance regulable control device, according in power distribution network each mutually between degree of unbalancedness Pun and A phase and B phase between line between reactive power Q ca between line between reactive power Q bc, C phase and A phase between line between reactive power Q ab, B phase and C phase, single-phase compensation capacitance group suitable in compensating unit between screening outlet, carry out single compensation balanced action, control the phase three-wire three combination switch switching compensating in capacitance group between this line, thus being switched on or switched off corresponding single-phase compensation electricity；RS485 communication modes is adopted, so that three-phase imbalance regulable control device controls the Guan Bi of each phase three-wire three combination switch or opens between three-phase imbalance regulable control device and each phase three-wire three combination switch；
(4) capacitance group work is compensated between the line filtered out, each the single-phase compensation electric capacity resolution of vectors in capacitance group is compensated between line, being decomposed into solution is the pure watt current contrary with each phase current of power distribution network and the pure reactive current vertical with each phase current, the pure watt current in opposite direction with power distribution network each phase watt current displaced place phase part active power, reaches the purpose of balanced load；90 ° of the advanced each phase current of the pure reactive current vertical with each phase current, thus compensate for place phase part reactive power, repeat the above steps (1) is to step (4), until Pun < K；
(5) three-phase imbalance regulable control device detects each phase power factor PFa, PFb, PFc, as PFa < K1 or PFb < K1, or (K1 is the limit value that unbalance control device sets according to the size of on-the-spot degree of unbalancedness during PFc < K1, span is between 0.95-0.98, the more high setting limit value of degree of unbalancedness is more high) start alternate compensating unit, filter out single-phase compensation capacitance group suitable in alternate compensating unit, compensate balance, control the phase three-wire three combination switch Guan Bi in this alternate compensation capacitance group, thus being switched on or switched off corresponding single-phase compensation electric capacity, until completing balanced compensated；RS485 communication modes is adopted between three-phase imbalance regulable control device and each phase three-wire three combination switch.
Between above-mentioned steps (3) center line, compensating unit 2 specific works is as follows, as it is shown on figure 3, in the distribution network of three-phase four-wire system, it is assumed that transformer low voltage output voltage amplitude is equal, phase 120 °.Namely there is Ua=U ∠ 0 °, Ub=U ∠-120 °, Uc=U ∠ 120 °, then have.If Qab is the condenser capacity being added in AB phase.Then for A phase, the capacitance current in AB phase.According to vector method, then Iabq=can be analyzed to the pure watt current Iap contrary with A phase current and the pure reactive current Iaq vertical with A phase current.Vectogram is as shown in Figure 3.As seen from the figure, the advanced A phase watt current of Iap 180 °, in opposite direction with A phase watt current, thus displaced A phase part active power, reach the purpose of balanced load；90 ° of the advanced A phase current of Iaq, thus compensate for A phase part reactive power.By that analogy, each electric capacity being connected between the line in each phase in compensating unit 2, compensate active power and reactive power that place is gone up mutually.
By above description it can be seen that this utility model size according to distribution transformer capacity, select compensating unit and alternate compensating unit between the line of phase suitable capacity, and power distribution network is respectively compensated by mutually, it is ensured that the alternate balancing the load between each phase of power distribution network；And, power distribution network three-phase imbalance described in the utility model regulates device and has the feature of versatility, without understanding load character and degree of unbalancedness during the installation of device, when not changing existing support structures, determine the capacity regulating device according to the capacity of transformator；In addition, the three-phase and four-line of device is connected after installing by device described in the utility model with the outfan of distribution transformer, and access corresponding current signal, three-phase imbalance regulable control device calculates active power and the reactive power of three-phase automatically, size automatic switching according to degree of unbalancedness, simple in construction, easy for installation, during work, temperature rise is low, the feature that loss is low.
Certainly, being more than representative instance of the present utility model, in addition, this utility model can also have other multiple detailed description of the invention, and all employings are equal to replacement or the technical scheme of equivalent transformation formation, all fall within the scope that this utility model claims.
Claims (2)
- null1. a power distribution network three-phase load self-checking device，It is installed in three-phase circuit system，It is characterized in that: include three-phase imbalance regulable control device、Compensating unit and alternate compensating unit between switching circuitry and the line that controlled by three-phase imbalance regulable control device，Between described line, compensating unit and alternate compensating unit are equipped with multiple compensation capacitance group according to the size of capacity，Each compensation capacitance group includes three single phase compensation capacitors，The A phase of described three-phase imbalance regulable control device and power distribution network、B phase is connected with C，Between described line, compensating unit compensates one end of three single phase compensation capacitors in capacitance group through switching circuitry respectively with the A phase of power distribution network、B phase is connected with C，The other end respectively with the B phase of power distribution network、C phase is connected with A phase，Described alternate compensating unit compensates three single phase compensation capacitor one end of capacitance group through switching circuitry respectively with the A phase of power distribution network、B phase is connected with C，The other end is all connected with the N line of power distribution network.
- 2. power distribution network three-phase load self-checking device according to claim 1, it is characterized in that: described switching circuitry includes phase three-wire three combination switch and miniature circuit breaker, phase three-wire three combination switch compensates capacitance group with each and is connected, and miniature circuit breaker is connected between each phase of power distribution network and phase three-wire three combination switch.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201620271441.XU CN205407281U (en) | 2016-04-01 | 2016-04-01 | Three phase load automatic regulating apparatus of distribution network |
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| CN201620271441.XU CN205407281U (en) | 2016-04-01 | 2016-04-01 | Three phase load automatic regulating apparatus of distribution network |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105656062A (en) * | 2016-04-01 | 2016-06-08 | 江苏盐开电气有限公司 | Power distribution network triphase load automatic adjusting device and control method thereof |
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2016
- 2016-04-01 CN CN201620271441.XU patent/CN205407281U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105656062A (en) * | 2016-04-01 | 2016-06-08 | 江苏盐开电气有限公司 | Power distribution network triphase load automatic adjusting device and control method thereof |
| CN105656062B (en) * | 2016-04-01 | 2018-05-08 | 江苏盐开电气有限公司 | Power distribution network three-phase load self-checking device and its control method |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20160727 Termination date: 20200401 |