CN204928179U - Reactive compensation , unbalanced three phase and low -voltage treatment system - Google Patents
Reactive compensation , unbalanced three phase and low -voltage treatment system Download PDFInfo
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- CN204928179U CN204928179U CN201520392404.XU CN201520392404U CN204928179U CN 204928179 U CN204928179 U CN 204928179U CN 201520392404 U CN201520392404 U CN 201520392404U CN 204928179 U CN204928179 U CN 204928179U
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
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Abstract
The utility model relates to a reactive compensation, unbalanced three phase and low -voltage treatment system. Unbalanced three phase and low -voltage treatment system be including being used for gathering acquisition unit, the control unit and the uneven compensation unit of three phase current and voltage, and uneven compensation unit is including appointing an at least compensating circuit who all connects between double -phase, and last string of compensating circuit is equipped with uneven building -out capacitor and control switch, and the control unit treatment system 1 control switch drops into and amputate corresponding building -out capacitor through corresponding treatment system 3. Unbalanced three phase and low -voltage improvement device include the controller, uneven building -out capacitor input method of operation and/or excision method in the controller. The utility model provides an unbalanced three phase and low -voltage improvement device and system can fast, accurately drop into or amputate the condenser to effectively improve the power factor of every looks, improve the imbalance degree between getting along with mutually, and can promote the phase voltage of every looks, and guarantee the stability and the reliability of compensation.
Description
Technical field
The utility model relates to reactive power compensation, three-phase imbalance and low-voltage governing system, belongs to electric network reactive compensation, three-phase imbalance and low-voltage Treatment process field.
Background technology
Along with national economy and scientific and technical high speed development, the living standard of resident is able to quick raising, the modernization household electrical appliance of various advanced person enter into family rapidly, the power load of resident also increases thereupon, the household electrical appliance that current resident uses are very different with in the past used, past is only incandescent lamp, electric rice cooker, electric frying pan, and be now electricity-saving lamp, refrigerator, range hood, hydraulic pressure TV, air-conditioning, electromagnetic oven, the various household electrical appliance such as washing machine, difference is in essence said from the angle of power load character, past electricity consumption is resistive load (power factor: COS Ф=1), and electricity consumption is now tending towards inductive load (power factor: COS Ф≤0.5).This just needs reactive power compensation with bring to power factor.
In addition low voltage electric network three-phase imbalance is exactly one of subject matter of puzzlement power supply unit always, and due to the existence of a large amount of single-phase load in city domestic power grid and agricultural power network, three alternate current imbalance phenomenons are particularly serious.Three-phase load unbalance, gently then reduces the power supplying efficiency of circuit and distribution transformer, heavy then can overload mutually too much because of heavy load, may cause that certain phase conductor blows, switch burns out the single-phase serious consequence such as to burn of even distribution transformer.
Three-phase imbalance specifically can cause following impact to circuit or equipment:
1, line loss and square to be directly proportional by electric current.Threephase load imbalance makes line loss greatly increase, if certain phase current is 3A, its aftercurrent is 0, if be evenly distributed to three-phase to become every phase 1A, then line loss will reduce to 1/3 of former line loss, in addition as considered, three-phase imbalance also can cause the neutral line to have electric current, and make the neutral line also produce loss, line loss can decline more.
2, distribution transformer is the power supply main equipment of low voltage electric network, when it runs under the uneven operating mode of threephase load, will cause the increase of distribution loss, because the power loss of distribution transforming is when load capacity is identical, its copper loss and iron loss and degree of unbalance are directly proportional.
In addition distribution transformer runs when threephase load is uneven, and its capacity exported just cannot reach rated value, and its reserve capacity is corresponding minimizing also, and overload capacity also reduces, and distribution transforming can be caused time serious to generate heat even scaling loss.
3, distribution transforming runs under the uneven operating mode of threephase load, and will produce zero-sequence current, this electric current will change with the unbalanced degree of threephase load, and degree of unbalance is larger, then zero-sequence current is also larger.
If operating distribution transforming exists zero-sequence current, then zero sequence fluxes will be produced in its iron core.(high-pressure side does not have zero-sequence current) this force zero sequence fluxes can only pass through using oil tank wall and steel beam column as passage, and the permeability of steel beam column is lower, when zero-sequence current is by steel beam column, namely to produce magnetic hysteresis and eddy current loss, thus make the steel beam column local temperature of distribution transforming raise heating.The winding insulation of distribution transforming is accelerated aging because of overheated, cause reduce equipment life.
4, when threephase load is uneven, distribution transformer each phase output current is just unequal, and its inner three-phase pressure drop is just unequal, and this will cause distribution transformer output voltage three-phase imbalance.When threephase load is simultaneously uneven, the neutral line just has electric current to be passed through.Thus make the neutral line produce impedance drop, thus cause neutral point drifting, cause each phase phase voltage to change.The phase voltage reduction that load is heavy, and the phase voltage rising that load is light, the power consumption equipment that phase connects easily causing voltage high burns out, and the power consumption equipment that phase connects that voltage is low then possibly cannot use.
Intelligent Reactive Compensating Controller is applicable to low-voltage distribution system, can be widely used in the enterprises such as outdoor desk-top transformer, interior distribution station, box-type substation and metallurgy, machinery, mine, railway, chemical industry or low-voltage customer carries out reactive-power automatic tracing compensation control.Controller is mainly used for the switching of control capacitor group, compensates control to the reactive power of electrical network, to reach the objects such as the load capacity of raising power factor and raising transformer.Control mode is generally divided into three-phase total compensation type, three-phase separate apotype, three-phase total compensation+point benefit mixed type three kinds.If application number is 02256020.3, the Chinese patent application file that utility model name is called " intellectual phase separate switching capacitance compensation power distribution equipment ", it discloses a kind of reactive power compensator, sampling unit gathers the electric current of three-phase and voltage and control unit is exported in Information Monitoring, control unit makes the judgement of reactive power compensation according to the information received, and then controls corresponding capacitor switching.This application does not provide a kind of effective reactive power compensator, and it can not solve three-phase imbalance and low-voltage problem.
Utility model content
The purpose of this utility model is to provide reactive power compensation, three-phase imbalance and low-voltage governing system, administers in order to carry out reactive power compensation, three-phase imbalance and low-voltage.
For achieving the above object, scheme of the present utility model comprises a kind of reactive power compensation, three-phase imbalance and low-voltage governing system, comprise the collecting unit for gathering three-phase current and voltage, control unit and imbalance compensation unit, described imbalance compensation unit comprises at least one compensated line of appointing and all connecting between two-phase, and on compensated line, string is provided with imbalance compensation electric capacity and control switch; Control switch described in described control unit control connection.
Two described compensated lines are all connected with between described two-phase.
Described reactive power compensation, three-phase imbalance and low-voltage governing system also comprise phase splitting compensation unit, and described phase splitting compensation unit comprises several phase splitting compensation electric capacity.
The utility model provides a kind of comparatively novel three-phase imbalance and low-voltage controlling device and system, this system comprises collecting unit, control unit and imbalance compensation unit for gathering three-phase current and voltage, imbalance compensation unit comprises at least one compensated line of appointing and all connecting between two-phase, on compensated line, string is provided with imbalance compensation electric capacity and control switch, control unit control connection control switch.
By comparing the specific relation between the active current of appointing two-phase, then after meeting other two conditions, drop into the imbalance compensation electric capacity on the line of this two-phase, capacitor can be dropped into quickly and accurately, thus effectively improve the power factor of every phase, improve degree of unbalance between phase and phase, and the phase voltage of every phase can be promoted, and ensure stability and the reliability of compensation.Achieve the optimal compensation to every in three-phase phase reactive power, low-voltage and three-phase imbalance.
When electric capacity excises, condition be according to three-phase active current between corresponding relation carry out judgement excision, another condition carries out judgement excision according to three-phase activity coefficient, these two conditions be or relation, corresponding electric capacity can be excised as long as there is one to satisfy condition, so this cutting method can carry out electric capacity excision effectively and quickly, ensure that the steady of power, avoid the situation of mending.
The three-phase imbalance that the utility model provides and low-voltage controlling device and system can separately for compensating reactive power, also can administer for three-phase load unbalance and low-voltage separately, also can two or three with the use of.The Main Function of the three-phase imbalance that the utility model provides and low-voltage controlling device and system is as follows:
1) electric energy loss of circuit is reduced;
2) reduce the electric energy loss of distribution transformer, improve transformer capacity utilance, reduce the maintenance cost of power distribution network;
3) reduce transformer zero-sequence current, improve power supply unit useful life, promote economic interests;
4) reduce line electricity pressure drop and unbalanced source voltage degree, thus improve the quality of power supply, remove power consumption equipment potential safety hazard.
Accompanying drawing explanation
Fig. 1 is the electric capacity for phase splitting compensation in imbalance compensation capacitor switching method embodiment 1 and annexation figure between three-phase line;
Fig. 2 is the electric capacity for imbalance compensation in imbalance compensation capacitor switching method embodiment 1 and annexation figure between three-phase line;
Fig. 3 is controller in imbalance compensation capacitor switching method embodiment 1 and the annexation figure between thyristor;
Fig. 4 is the structure chart of the three-phase imbalance controller in imbalance compensation capacitor switching method embodiment 1;
Fig. 5 is electric capacity in imbalance compensation capacitor switching method embodiment 2 and annexation figure between three-phase line;
Fig. 6 is controller in imbalance compensation capacitor switching method embodiment 2 and the annexation figure between thyristor.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in more detail.
Imbalance compensation capacitor switching method embodiment 1
As shown in Figure 1, for for the annexation figure between the electric capacity of phase splitting compensation and three-phase line.Between A phase and zero line, there are two connection lines, a circuit are serially connected with thyristor TSC-1 and electric capacity successively, another circuit is serially connected with thyristor TSC-2 and electric capacity successively; Between B phase and zero line, there are two connection lines, a circuit are serially connected with thyristor TSC-3 and electric capacity successively, another circuit is serially connected with thyristor TSC-4 and electric capacity successively; Between C phase and zero line, there are two connection lines, a circuit are serially connected with thyristor TSC-5 and electric capacity successively, another circuit is serially connected with thyristor TSC-6 and electric capacity successively.As shown in Figure 2, for for annexation figure between the electric capacity of imbalance compensation and three-phase line.Between A phase and B phase, there are two compensated lines, a circuit are serially connected with thyristor TSC-7 and electric capacity successively, another circuit is serially connected with thyristor TSC-8 and electric capacity successively; Between B phase and C phase, there are two compensated lines, a circuit are serially connected with thyristor TSC-9 and electric capacity successively, another circuit is serially connected with thyristor TSC-10 and electric capacity successively; Between C phase and A phase, there are two compensated lines, a circuit are serially connected with thyristor TSC-11 and electric capacity successively, another circuit is serially connected with thyristor TSC-12 and electric capacity successively.
Three-phase imbalance low-voltage governing system comprises collecting unit, control unit, imbalance compensation unit and phase splitting compensation unit for gathering three-phase current and voltage, collecting unit adopts the device of collection three-phase current of the prior art and voltage, such as: gather electric current and make Current Transformer, gather that voltage is then direct to be connected on three-phase line by collection circuit, the collection signal input of collecting unit connection control unit.Imbalance compensation unit comprises above-mentioned 6 compensated lines mentioned, and has two compensated lines between every two-phase, and as shown in Figure 3, imbalance compensation unit comprises 6 electric capacity and 6 thyristors.Control unit is three-phase imbalance controller, and the control signal output of three-phase imbalance controller connects all thyristors.
Be illustrated in figure 4 the structure chart of three-phase imbalance controller.The electric capacity that A3, A4, B3, B4, C3, C4 lead-out terminal on three-phase imbalance controller is corresponding is used for meritorious imbalance compensation; The electric capacity that A1 and A2 lead-out terminal on three-phase imbalance controller is corresponding is used for A phase power factor phase splitting compensation, and the electric capacity that B1 and B2 is corresponding is used for B phase power factor phase splitting compensation, and the electric capacity that C1 and C2 is corresponding is used for C phase power factor phase splitting compensation.These 6 terminal functions of A1, A2, B1, B2, C1 and C2 are identical with the terminal function that controller of the prior art controls phase splitting compensation.Unlike the prior art, preferential switching A3, A4, B3, B4, C3, C4 during compensation.
The compensation of pre-emptive power factor when unbalanced power compensates.
First, default objects power-factor cos ψ is set
target.Setting electric capacity that A3, A4, B3, B4, C3, C4 connect is respectively C
a3, C
a4, C
b3, C
b4, C
c3, C
c4, corresponding rated capacity is respectively S
a3, S
a4, S
b3, S
b4, S
c3, S
c4, setting accuracy is less than 1kvar.
Context between A, B, C three-phase is: the advanced A phase 120 DEG C of B phase, the advanced B phase 120 DEG C of C phase, the advanced C phase 120 DEG C of A phase.If A, B, C three-phase active current size is respectively I
a, I
b, I
cif A, B, C three-phase activity coefficient is respectively cos ψ
a, cos ψ
b, cos ψ
c.
The control method of reactive power compensation is:
First control C
a3, C
a4, C
b3, C
b4, C
c3, C
c4input, be divided into three kinds of situations: control C
a3, C
a4input, control C
b3, C
b4input, control C
c3, C
c4input.
The first, control C
a3, C
a4input
Detect A phase and B phase active current size;
Controller judges whether following three conditions are set up:
Condition is 1.: I
a﹥ I
b+ 1.5S
a3;
Condition is 2.: A phase drops into C
a3rear cos ψ
a﹤ 1 is (if A phase drops into C
a3rear cos ψ
a﹤ 1 does not meet, and now electric capacity that A1, A2 connect has dropped into, now as A1, A2 connect electric capacity close, cos ψ
a﹤ 1 meets, and so electric capacity that A1, A2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: B phase drops into C
a3rear cos ψ
b﹤ 1 is (if B phase drops into C
a3rear cos ψ
b﹤ 1 does not meet, and now electric capacity that B1, B2 connect has dropped into, now as B1, B2 connect electric capacity close, cos ψ
b﹤ 1 meets, and so electric capacity that B1, B2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the A3 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
a3; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the A3 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
a3.
At C
a3after input, controller judges whether following three conditions are set up:
Condition is 1.: I
a﹥ I
b+ 1.5S
a3;
Condition is 2.: A phase drops into C
a4rear cos ψ
a﹤ 1 is (if A phase drops into C
a4rear cos ψ
a﹤ 1 does not meet, and now electric capacity that A1, A2 connect has dropped into, now as A1, A2 connect electric capacity close, cos ψ
a﹤ 1 meets, and so electric capacity that A1, A2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: B phase drops into C
a4rear cos ψ
b﹤ 1 is (if B phase drops into C
a4rear cos ψ
b﹤ 1 does not meet, and now electric capacity that B1, B2 connect has dropped into, now as B1, B2 connect electric capacity close, cos ψ
b﹤ 1 meets, and so electric capacity that B1, B2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the A4 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
a4; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the A4 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
a4.
The second, control C
b3, C
b4input
Detect B phase and C phase active current size;
Controller judges whether following three conditions are set up:
Condition is 1.: I
b﹥ I
c+ 1.5S
b3;
Condition is 2.: B phase drops into C
b3rear cos ψ
b﹤ 1 is (if B phase drops into C
b3rear cos ψ
b﹤ 1 does not meet, and now electric capacity that B1, B2 connect has dropped into, now as B1, B2 connect electric capacity close, cos ψ
b﹤ 1 meets, and so electric capacity that B1, B2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: C phase drops into C
b3rear cos ψ
c﹤ 1 is (if C phase drops into C
b3rear cos ψ
c﹤ 1 does not meet, and now electric capacity that C1, C2 connect has dropped into, now as C1, C2 connect electric capacity close, cos ψ
c﹤ 1 meets, and so electric capacity that C1, C2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the B3 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
b3; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the B3 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
b3.
At C
b3after input, controller judges whether following three conditions are set up:
Condition is 1.: I
b﹥ I
c+ 1.5S
b3;
Condition is 2.: B phase drops into C
b4rear cos ψ
b﹤ 1 is (if B phase drops into C
b4rear cos ψ
b﹤ 1 does not meet, and now electric capacity that B1, B2 connect has dropped into, now as B1, B2 connect electric capacity close, cos ψ
b﹤ 1 meets, and so electric capacity that B1, B2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: C phase drops into C
b4rear cos ψ
c﹤ 1 is (if C phase drops into C
b4rear cos ψ
c﹤ 1 does not meet, and now electric capacity that C1, C2 connect has dropped into, now as C1, C2 connect electric capacity close, cos ψ
c﹤ 1 meets, and so electric capacity that C1, C2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the B4 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
b4; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the B4 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
b4.
The third, control C
c3, C
c4input
Detect C phase and A phase active current size;
Controller judges whether following three conditions are set up:
Condition is 1.: I
c﹥ I
a+ 1.5S
c3;
Condition is 2.: C phase drops into C
c3rear cos ψ
c﹤ 1 is (if C phase drops into C
c3rear cos ψ
c﹤ 1 does not meet, and now electric capacity that C1, C2 connect has dropped into, now as C1, C2 connect electric capacity close, cos ψ
c﹤ 1 meets, and so electric capacity that C1, C2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: A phase drops into C
c3rear cos ψ
a﹤ 1 is (if A phase drops into C
c3rear cos ψ
a﹤ 1 does not meet, and now electric capacity that A1, A2 connect has dropped into, now as A1, A2 connect electric capacity close, cos ψ
a﹤ 1 meets, and so electric capacity that A1, A2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the C3 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
c3; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the C3 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
c3.
At C
c3after input, controller judges whether following three conditions are set up:
Condition is 1.: I
c﹥ I
a+ 1.5S
c3;
Condition is 2.: C phase drops into C
c4rear cos ψ
c﹤ 1 is (if C phase drops into C
c4rear cos ψ
c﹤ 1 does not meet, and now electric capacity that C1, C2 connect has dropped into, now as C1, C2 connect electric capacity close, cos ψ
c﹤ 1 meets, and so electric capacity that C1, C2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: A phase drops into C
c4rear cos ψ
a﹤ 1 is (if A phase drops into C
c4rear cos ψ
a﹤ 1 does not meet, and now electric capacity that A1, A2 connect has dropped into, now as A1, A2 connect electric capacity close, cos ψ
a﹤ 1 meets, and so electric capacity that A1, A2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the C4 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
c4; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the C4 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
c4.
If C
a3, C
a4, C
b3, C
b4, C
c3, C
c4after electric capacity drops into, power factor is still lower than desired value, so, then by phase splitting compensation strategy process terminal A1, A2, B1, B2, C1, C2 connect the switching of electric capacity.This belongs to phase splitting compensation of the prior art, does not repeat here.
As control C
a3, C
a4, C
b3, C
b4, C
c3, C
c4excision time, be divided into two steps, wherein step one be according to three-phase active current between corresponding relation judge, step 2 judges according to three-phase activity coefficient.If step one can realize the excision of electric capacity, so just without the need to step 2; If step one can not realize the excision of electric capacity, so, just need step 2 continue judgement excise, that is, step one and step 2 be or logical relation.And do not have strict context between step one and step 2, the tandem of two steps can be exchanged.
When judging according to the corresponding relation between three-phase active current, be also divided into three kinds of situations: control C
a3, C
a4excision, control C
b3, C
b4excision, control C
c3, C
c4excision.
Control C
a3, C
a4excision:
Controller judges I
b﹥ I
a+ 1.5S
a3whether set up; If set up, now excise C
a3, namely A3 terminal exports is 0; Excision C
a3rear judgement I
b﹥ I
a+ 1.5S
a4whether set up, if set up, now excise C
a4, namely A4 terminal exports is 0.
Control C
b3, C
b4excision:
Controller judges I
c﹥ I
b+ 1.5S
b3whether set up; If set up, now excise C
b3, namely B3 terminal exports is 0; Excision C
b3rear judgement I
c﹥ I
b+ 1.5S
b4whether set up, if set up, now excise C
b4, namely B4 terminal exports is 0.
Control C
c3, C
c4excision:
Controller judges I
a﹥ I
c+ 1.5S
c3whether set up; If set up, now excise C
c3, namely C3 terminal exports is 0; Excision C
c3rear judgement I
a﹥ I
c+ 1.5S
c4whether set up, if set up, now excise C
c4, namely C4 terminal exports is 0.
When judging according to three-phase activity coefficient, namely whether there is the excision covering row electric capacity to judge mutually according to every in three-phase, being divided into following three kinds of situations:
One, cos ψ is detected
a:
If cos is ψ
a=1 or by negative value time: being connect electric capacity by point mending process A1 and A2, excising after A1 and A2 connect electric capacity, again judging cos ψ
abe whether 1 or be negative value (if when reactive power compensation, do not carry out phase splitting compensation, so, just do not need this step), if cos is ψ
a=1 or be negative value time, be handled as follows: compare I
b-I
awith I
a-I
csize:
As I
b-I
a﹥ I
a-I
c(considering positive and negative), then first excise C
a3, C
a4, rear excision C
c3, C
c4; As I
b-I
a< I
a-I
c(considering positive and negative), then first excise C
c3, C
c4, rear excision C
a3, C
a4, until only mend.Often excise one group of electric capacity in excision process just to need to compare I
b-I
awith I
a-I
csize once, then according to result judge excision priority.
Two, cos ψ is detected
b:
If cos is ψ
b=1 or be negative value time, by point mending treatments B 1 and an electric capacity that B2 connects, excising after B1 and B2 connect electric capacity, again judging cos ψ
bbe whether 1 or be negative value (if when reactive power compensation, do not carry out phase splitting compensation, so, just do not need this step), if cos is ψ
b=1 or be negative value time, be handled as follows: compare I
b-I
awith I
c-I
bsize:
As I
b-I
a﹥ I
c-I
b(considering positive and negative), then first excise C
a3, C
a4, rear excision C
b3, C
b4; As I
b-I
a< I
c-I
b(considering positive and negative), then first excise C
b3, C
b4, rear excision C
a3, C
a4, until only mend.Often excise one group of electric capacity in excision process just to need to compare I
b-I
awith I
c-I
bsize once, then according to result judge excision priority.
Three, cos ψ is detected
c:
If cos is ψ
c=1 or be negative value time, by point mending a process electric capacity that C1 and C2 connects, excising after C1 and C2 connect electric capacity, again judging cos ψ
cbe whether 1 or be negative value (if when reactive power compensation, do not carry out phase splitting compensation, so, just do not need this step), if cos is ψ
c=1 or be negative value time, be handled as follows: compare I
a-I
cwith I
c-I
bsize:
As I
a-I
c﹥ I
c-I
b(considering positive and negative), then first excise C
a3, C
a4, rear excision C
b3, C
b4; As I
a-I
c< I
c-I
b(considering positive and negative), then first excise C
b3, C
b4, rear excision C
a3, C
a4, until only mend.Often excise one group of electric capacity in excision process just to need to compare I
a-I
cwith I
c-I
bsize once, then according to result judge excision priority.
In above-described embodiment, reactive power compensator comprises phase splitting compensation unit, and when imbalance compensation can not complete idle compensation, then carry out phase splitting compensation, this phase splitting compensation belongs to prior art.As other embodiment, when imbalance compensation can complete idle compensation, this reactive power compensator can not have phase splitting compensation unit.
In above-described embodiment, control switch is thyristor, controller controls the break-make of thyristor to realize the switching of electric capacity, as other embodiment, control switch can also be other on-off switch, such as: relay, the contact of relay and capacitances in series, the coil of controller control connection relay, the coil of relay obtains the correspondingly contact conducting of control relay or the shutoff of electric or dead electricity.
Imbalance compensation capacitor switching method embodiment 2
The difference of the present embodiment and above-mentioned imbalance compensation capacitor switching method embodiment 1 is: have two compensated lines in embodiment 1 between phase and phase, every bar compensated line is all serially connected with thyristor and electric capacity, when carrying out the input of electric capacity, the control that two electric capacity needs priority to carry out dropping into, and in the present embodiment, only have a compensated line between phase and phase, this circuit is serially connected with thyristor and electric capacity, when carrying out the input of electric capacity, only need an input control.Wherein, as shown in Figure 5, the annexation between controller and electric capacity as shown in Figure 6 for the annexation between electric capacity and three-phase line.
Imbalance compensation capacitor switching method is specific as follows:
The electric capacity that A3, B3, C3 lead-out terminal on three-phase imbalance controller is corresponding is used for meritorious imbalance compensation.Due to the emphasis that phase splitting compensation is not the present embodiment, in the same manner as in Example 1 here.
First, default objects power-factor cos ψ is set
target.Setting electric capacity that A3, B3, C3 connect is respectively C
a3, C
b3, C
c3, corresponding rated capacity is respectively S
a3, S
b3, S
c3, setting accuracy is less than 1kvar.
Context between A, B, C three-phase is: the advanced A phase 120 DEG C of B phase, the advanced B phase 120 DEG C of C phase, the advanced C phase 120 DEG C of A phase.If A, B, C three-phase active current size is respectively I
a, I
b, I
cif A, B, C three-phase activity coefficient is respectively cos ψ
a, cos ψ
b, cos ψ
c.
The control method of reactive power compensation is:
First control C
a3, C
b3, C
c3input, be divided into three kinds of situations: control C
a3input, control C
b3input, control C
c3input.
The first, control C
a3input
Detect A phase and B phase active current size;
Controller judges whether following three conditions are set up:
Condition is 1.: I
a﹥ I
b+ 1.5S
a3;
Condition is 2.: A phase drops into C
a3rear cos ψ
a﹤ 1 is (if A phase drops into C
a3rear cos ψ
a﹤ 1 does not meet, and now electric capacity that A1, A2 connect has dropped into, now as A1, A2 connect electric capacity close, cos ψ
a﹤ 1 meets, and so electric capacity that A1, A2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: B phase drops into C
a3rear cos ψ
b﹤ 1 is (if B phase drops into C
a3rear cos ψ
b﹤ 1 does not meet, and now electric capacity that B1, B2 connect has dropped into, now as B1, B2 connect electric capacity close, cos ψ
b﹤ 1 meets, and so electric capacity that B1, B2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the A3 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
a3; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the A3 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
a3.
The second, control C
b3input
Detect B phase and C phase active current size;
Controller judges whether following three conditions are set up:
Condition is 1.: I
b﹥ I
c+ 1.5S
b3;
Condition is 2.: B phase drops into C
b3rear cos ψ
b﹤ 1 is (if B phase drops into C
b3rear cos ψ
b﹤ 1 does not meet, and now electric capacity that B1, B2 connect has dropped into, now as B1, B2 connect electric capacity close, cos ψ
b﹤ 1 meets, and so electric capacity that B1, B2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: C phase drops into C
b3rear cos ψ
c﹤ 1 is (if C phase drops into C
b3rear cos ψ
c﹤ 1 does not meet, and now electric capacity that C1, C2 connect has dropped into, now as C1, C2 connect electric capacity close, cos ψ
c﹤ 1 meets, and so electric capacity that C1, C2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the B3 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
b3; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the B3 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
b3.
The third, control C
c3input
Detect C phase and A phase active current size;
Controller judges whether following three conditions are set up:
Condition is 1.: I
c﹥ I
a+ 1.5S
c3;
Condition is 2.: C phase drops into C
c3rear cos ψ
c﹤ 1 is (if C phase drops into C
c3rear cos ψ
c﹤ 1 does not meet, and now electric capacity that C1, C2 connect has dropped into, now as C1, C2 connect electric capacity close, cos ψ
c﹤ 1 meets, and so electric capacity that C1, C2 connect is closed, and is then considered as this condition and meets);
Condition is 3.: A phase drops into C
c3rear cos ψ
a﹤ 1 is (if A phase drops into C
c3rear cos ψ
a﹤ 1 does not meet, and now electric capacity that A1, A2 connect has dropped into, now as A1, A2 connect electric capacity close, cos ψ
a﹤ 1 meets, and so electric capacity that A1, A2 connect is closed, and is then considered as this condition and meets);
If above-mentioned three conditions meet simultaneously, then the C3 terminal of controller exports high level signal 1, and turn on thyristors, namely drops into C
c3; Otherwise as long as have 1 condition not meet in above-mentioned three conditions, the C3 terminal of controller is low level signal 0 always, thyristor disconnects, and does not namely drop into C
c3.
If C
a3, C
b3, C
c3after electric capacity drops into, power factor is still lower than desired value, so, then by phase splitting compensation strategy process terminal A1, A2, B1, B2, C1, C2 connect the switching of electric capacity.This belongs to phase splitting compensation of the prior art, does not repeat here.
As control C
a3, C
b3, C
c3excision time, be divided into two steps, wherein step one be according to three-phase active current between corresponding relation judge, step 2 judges according to three-phase activity coefficient.If step one can realize the excision of electric capacity, so just without the need to step 2; If step one can not realize the excision of electric capacity, so, just need step 2 continue judgement excise, that is, step one and step 2 be or logical relation.And do not have strict context between step one and step 2, the tandem of two steps can be exchanged.
When judging according to the corresponding relation between three-phase active current, be also divided into three kinds of situations: control C
a3excision, control C
b3excision, control C
c3excision.
Control C
a3excision:
Controller judges I
b﹥ I
a+ 1.5S
a3whether set up; If set up, now excise C
a3, namely A3 terminal exports is 0.
Control C
b3excision:
Controller judges I
c﹥ I
b+ 1.5S
b3whether set up; If set up, now excise C
b3, namely B3 terminal exports is 0.
Control C
c3excision:
Controller judges I
a﹥ I
c+ 1.5S
c3whether set up; If set up, now excise C
c3, namely C3 terminal exports is 0.
When judging according to three-phase activity coefficient, namely whether there is the excision covering row electric capacity to judge mutually according to every in three-phase, being divided into following three kinds of situations:
One, cos ψ is detected
a:
If cos is ψ
a=1 or by negative value time: being connect electric capacity by point mending process A1 and A2, excising after A1 and A2 connect electric capacity, again judging cos ψ
abe whether 1 or be negative value (if when reactive power compensation, do not carry out phase splitting compensation, so, just do not need this step), if cos is ψ
a=1 or be negative value time, be handled as follows: compare I
b-I
awith I
a-I
csize:
As I
b-I
a﹥ I
a-I
c(considering positive and negative), then first excise C
a3, rear excision C
c3; As I
b-I
a< I
a-I
c(considering positive and negative), then first excise C
c3, rear excision C
a3, until only mend.Often excise one group of electric capacity in excision process just to need to compare I
b-I
awith I
a-I
csize once, then according to result judge excision priority.
Two, cos ψ is detected
b:
If cos is ψ
b=1 or be negative value time, by point mending treatments B 1 and an electric capacity that B2 connects, excising after B1 and B2 connect electric capacity, again judging cos ψ
bbe whether 1 or be negative value (if when reactive power compensation, do not carry out phase splitting compensation, so, just do not need this step), if cos is ψ
b=1 or be negative value time, be handled as follows: compare I
b-I
awith I
c-I
bsize:
As I
b-I
a﹥ I
c-I
b(considering positive and negative), then first excise C
a3, rear excision C
b3; As I
b-I
a< I
c-I
b(considering positive and negative), then first excise C
b3, rear excision C
a3, until only mend.Often excise one group of electric capacity in excision process just to need to compare I
b-I
awith I
c-I
bsize once, then according to result judge excision priority.
Three, cos ψ is detected
c:
If cos is ψ
c=1 or be negative value time, by point mending a process electric capacity that C1 and C2 connects, excising after C1 and C2 connect electric capacity, again judging cos ψ
cbe whether 1 or be negative value (if when reactive power compensation, do not carry out phase splitting compensation, so, just do not need this step), if cos is ψ
c=1 or be negative value time, be handled as follows: compare I
a-I
cwith I
c-I
bsize:
As I
a-I
c﹥ I
c-I
b(considering positive and negative), then first excise C
a3, rear excision C
b3; As I
a-I
c< I
c-I
b(considering positive and negative), then first excise C
b3, rear excision C
a3, until only mend.Often excise one group of electric capacity in excision process just to need to compare I
a-I
cwith I
c-I
bsize once, then according to result judge excision priority.
In above-described embodiment, reactive power compensation, three-phase imbalance and low-voltage controlling device comprise phase splitting compensation unit, and when imbalance compensation can not complete idle compensation, then carry out phase splitting compensation, this phase splitting compensation belongs to prior art.As other embodiment, when imbalance compensation can complete idle compensation, this reactive power compensator can not have phase splitting compensation unit.
In above-described embodiment, control switch is thyristor, controller controls the break-make of thyristor to realize the switching of electric capacity, as other embodiment, control switch can also be other on-off switch, such as: relay, the contact of relay and capacitances in series, the coil of controller control connection relay, the coil of relay obtains the correspondingly contact conducting of control relay or the shutoff of electric or dead electricity.
In above-mentioned imbalance compensation capacitor switching method embodiment 1 and embodiment 2, appoint the compensated line between two-phase to be respectively one and two, certainly, can also be more, no matter be how many compensated lines, the operation/cutting method of the electric capacity of its correspondence is identical.
Three-phase imbalance and low-voltage governing system embodiment 1
Three-phase imbalance in the present embodiment and low-voltage governing system are described later in detail in imbalance compensation capacitor switching method embodiment 1, do not repeat at this.
Three-phase imbalance and low-voltage governing system embodiment 2
Three-phase imbalance in the present embodiment and low-voltage governing system embodiment are described later in detail in imbalance compensation capacitor switching method embodiment 2, do not repeat at this.
Three-phase imbalance and low-voltage controlling device embodiment 1
The embodiment of this device is identical with low-voltage governing system embodiment 1 with three-phase imbalance, does not repeat here.
Three-phase imbalance and low-voltage controlling device embodiment 2
The embodiment of this device is identical with low-voltage governing system embodiment 2 with three-phase imbalance, does not repeat here.
Be presented above concrete execution mode, but the utility model is not limited to described execution mode.The change carried out execution mode when not departing from principle of the present utility model and spirit, amendment, replacement and modification still fall in protection range of the present utility model.
Claims (3)
1. a reactive power compensation, three-phase imbalance and low-voltage governing system, it is characterized in that, comprise the collecting unit for gathering three-phase current and voltage, control unit and imbalance compensation unit, described imbalance compensation unit comprises at least one compensated line of appointing and all connecting between two-phase, and on compensated line, string is provided with imbalance compensation electric capacity and control switch; Control switch described in described control unit control connection.
2. reactive power compensation according to claim 1, three-phase imbalance and low-voltage governing system, is characterized in that, is all connected with two described compensated lines between described two-phase.
3. reactive power compensation according to claim 1 and 2, three-phase imbalance and low-voltage governing system, it is characterized in that, described reactive power compensation, three-phase imbalance and low-voltage governing system also comprise phase splitting compensation unit, and described phase splitting compensation unit comprises several phase splitting compensation electric capacity.
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Cited By (1)
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|---|---|---|---|---|
| CN104852398A (en) * | 2015-06-09 | 2015-08-19 | 河南博通电力技术有限公司 | Three-phase imbalance and low-voltage treatment device and system, and compensation loop switching method |
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2015
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104852398A (en) * | 2015-06-09 | 2015-08-19 | 河南博通电力技术有限公司 | Three-phase imbalance and low-voltage treatment device and system, and compensation loop switching method |
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