CN104269864A - Contactor switching reactive compensation method based on response periodical prediction - Google Patents

Abstract

The invention belongs to the technical field of electric energy quality control, and relates to a contactor switching reactive compensation method based on response periodical prediction to solve the problem that in the prior art, the response time of a contactor is hard to predict, the accurate zero-crossing-point switching cannot be achieved. The method comprises the following steps that firstly, a three-phase voltage signal, a three-phase current signal, a zero-cross detection signal of the voltage at the two ends of the contactor and the current working environment temperature of a device are collected as detection signals; secondly, the detection signals are processed through a signal conditioning module, and the processed detection signals are sent to a control module; thirdly, the current system power factor is calculated; fourthly, when the power factor is smaller than or equal to the turn-on threshold value, the fifth step is executed, when the power factor is larger than or equal to the turn-off threshold value, the sixth step is executed, and when the power factor is between the turn-on threshold value and the turn-off threshold value, the previous state is kept; fifthly, the control module sends an input compensation order, and the fourth step is executed; sixthly, the control module sends a switching instruction, and the third step is executed.

Description

Based on the contactor switching reactive-load compensation method of response cycle prediction

Technical field

The present invention relates to based on a kind of accurate prediction to contactor response cycle thus realize the contactor switching reactive power compensation technology (HVC) of operating passing zero, to maintain the stability of electrical network, belonging to power quality control technology field.

Background technology

Contactor switching reactive power compensation technology (HVC) is the technology relying on contactless contactor input capacitor to carry out reactive power in dynamic compensation electrical network, low with its price, reliability is high, be convenient to safeguard, electric pressure is high, not by advantages such as power electronic device resistance to pressure restrictions, in high-pressure reactive compensation field, application is very general.

Traditional HVC device is random for choosing of contactless contactor moment in control, and depends on manually or protective relaying device action.This control mode does not obviously meet the control overflow of automation, and due to the random break-make of contactless contactor, immediate current can be brought to shove and the series of negative effect such as overvoltage, even may cause burning of compensation arrangement, the stable operation of harm electrical network.

That studies focuses on by detecting the zero crossing of fixed phase, adopts the automatic control contactor of intelligent controller open-minded at voltage over zero, turns off at current zero-crossing point, thus effectively suppresses the negative effect that switching building-out capacitor produces instantaneously.But because HVC device employing contactor is as fling-cut switch, and contactor belongs to mechanical switch, its response time changes by the change of environmental factor, the accuracy of electronic switch cannot be reached, this adds difficulty with regard to giving the realization of synchronous switching technology, namely the contactor response time is difficult to prediction, causes and cannot realize accurate zero crossing switching.

Summary of the invention

The present invention seeks to be difficult to prediction to solve the contactor response time in prior art, causing the problem that cannot realize accurate zero crossing switching, providing a kind of contactor switching reactive-load compensation method based on response cycle prediction.

Contactor switching reactive-load compensation method based on response cycle prediction of the present invention, adopt the mode of contactor switched capacitor to carry out reactive power compensation, it is characterized in that, the method comprises the following steps:

Step one, gather the three-phase voltage signal u of described contactor place electrical network _a, u _b, u _cwith three-phase current signal i _a, i _b, i _c, the zero passage detection signal of contactor both end voltage and the ambient temperature of device work at present, as detection signal;

Step 2, by Signal-regulated kinase, the detection signal that step one obtains to be processed, and the detection signal after process is sent into control module;

Step 3, in the control module, according to the detection signal after process, and adopts instantaneous reactive power theory to calculate the power factor of current system;

Step 4, judge the size of the power factor of current system, perform corresponding operating according to condition;

When power factor be less than or equal to open threshold value time, perform step 5;

When power factor is more than or equal to shutoff threshold value, perform step 6;

When power factor is in time opening threshold value and turn off between threshold value, keep laststate;

Step 5, control module send input compensation instruction, make contactor perform closing operation, carry out reactive power compensation by drive circuit; Return execution step 4;

Step 6, control module send switching instruction, make contactor perform sub-switching operation, then return execution step 3 by drive circuit.

Advantage of the present invention: the present invention proposes a kind of contactor switching compensating power based on response cycle prediction and make capacitor reach the technology of operating passing zero accurately.The maximum feature of the present invention is can by contactor response cycle warehouse-in last time, the response cycle of last time is directly called as reference value when next switching, affecting the problem of response cycle without the need to worrying the friction caused because the contactor operating time is elongated to become large, reaching response cycle from model-following control.Utilize certain oilfield electric net reactive power compensation field measurement data analysis also to demonstrate and adopt response cycle from model-following control, can the action of control contactor time be engraved in its both end voltage electric current real zero-crossing point ± 1ms error range in, thus effectively avoid switching moment issuable voltage current impact problem.The results show control method of the present invention reaches the accurate operating passing zero effect of expection, avoids the switching moment negative effect such as issuable surge current and overvoltage, can ensure the stable operation of HVC device.

Due to the uncertainty of operating voltage and variation of ambient temperature, the data sample of response cycle is difficult to meet completely the demand that HVC operating passing zero controls sometimes, needs to study a kind of method of carrying out on-the-spot period forecasting analysis.By to the analysis of contactor response cycle influencing factor and experiment test, obtain the Changing Pattern analytical expression that ambient temperature under specific operation voltage conditions affects contactor response cycle, provide the contactor response cycle value at varying environment temperature accordingly, achieve the Accurate Prediction to contactor response cycle.

Adopt contactor synchronous switched capacitor be solve reactive power compensator high voltage that current quality of power supply field exists, high power level, low cost problem provide new thinking, has very high using value.The present invention can need the reactive power that compensates by dynamic real-time monitoring system, realizes the accurate operating passing zero of contactor switching capacitance, can ensure the power supply quality of electrical network, improve the electrical safety of load, ensure that it is efficient, safe and stable operation.

Accompanying drawing explanation

Fig. 1 is HVC reactive power compensator system block diagram, and whole system is made up of a few parts such as Signal-regulated kinase, control module, driver module and reactive compensation modules, and wherein in figure, A, B, C are three-phase alternating current in electrical network, i _a, i _b, i _cfor electrical network three-phase current signal, u _a, u _b, u _cfor electrical network three-phase voltage signal, compensating module adopts vacuum contactor as the switching device of switching building-out capacitor.

Fig. 2 is the HVC device topology diagram of the present invention when specifically implementing, and adopt the value mode of 8421 to choose, its capacity is respectively 30kVar, 60kVar, 120kVar, and three-phase condenser bank adopts dihedral to connect.

Fig. 3 is the synchronous switching control block diagram of contactor.

Fig. 4 is synchronous switching combined floodgate scheme schematic diagram, t _sfor system sends the moment of input compensation instruction, zero cross detection circuit is with A phase voltage zero crossing for benchmark, t _abe monitor the zero crossing moment nearest with input compensation instruction, Δ t sends input compensation instruction to time A phase voltage zero crossing being detected, t _on-jfor the delay time determined according to the ambient temperature of contactor work at present, A ₀for the true fixed phase point of contactor actual act, t _dA-j, t _dB-j, t _dC-jbe respectively the minimum delay time of three-phase.

Fig. 5 is synchronous switching separating brake scheme schematic diagram.

Fig. 6 is contactor response time testing circuit, and STM32ARM single-chip microcomputer is issued to from control signal the realistic operation time that the time difference of generation current loop is contactor by detecting.

Fig. 7 is experiment contactor combined floodgate oscillogram.

Fig. 8 is experiment contactor separating brake oscillogram.

Fig. 9 is the system flow chart of HVC device, and wherein scheming a) is the main flow chart of HVC device, and figure is b) synchronous switching subroutine flow chart.

Figure 10 is that the non-zero passage of contactor drops into oscillogram.

Figure 11 is the non-operating passing zero oscillogram of contactor.

Figure 12 is contactor zero passage input oscillogram first.

Figure 13 is contactor operating passing zero oscillogram first.

Figure 14 is that contactor second time zero passage drops into oscillogram.

Figure 15 is contactor second time operating passing zero oscillogram.

Embodiment

Embodiment one: present embodiment is described below in conjunction with Fig. 1, based on the contactor switching reactive-load compensation method of response cycle prediction described in present embodiment, adopt the mode of contactor switched capacitor to carry out reactive power compensation, it is characterized in that, the method comprises the following steps:

Step one, gather the three-phase voltage signal u of described contactor place electrical network _a, u _b, u _cwith three-phase current signal i _a, i _b, i _c, the zero passage detection signal of contactor both end voltage and the ambient temperature of device work at present, as detection signal;

Step 2, by Signal-regulated kinase, the detection signal that step one obtains to be processed, and the detection signal after process is sent into control module;

Step 3, in the control module, according to the detection signal after process, and adopts instantaneous reactive power theory to calculate the power factor of current system;

Step 4, judge the size of the power factor of current system, perform corresponding operating according to condition;

When power factor be less than or equal to open threshold value time, perform step 5;

When power factor is more than or equal to shutoff threshold value, perform step 6;

When power factor is in time opening threshold value and turn off between threshold value, keep laststate;

Step 5, control module send input compensation instruction, make contactor perform closing operation, carry out reactive power compensation by drive circuit; Return execution step 4;

Step 6, control module send switching instruction, make contactor perform sub-switching operation, then return execution step 3 by drive circuit.

In step one, gather the three-phase voltage signal u of described contactor place electrical network _a, u _b, u _cfor determining that the zero crossing of A phase voltage is prepared.Gather three-phase current signal i _a, i _b, i _cfor rated output factor.During system works, by current sensor and voltage sensor acquisition system three-phase current signal and three-phase voltage signal, the parameter such as reactive power, power factor of Real-Time Monitoring electrical network.The amplitude range of the signal that can receive due to system core control unit is 0-3.3V, the output level of current sensor and voltage sensor directly can not send into the inside A/D of controller, need to send into signal conditioning circuit through carrying out amplifying, lifting, by voltage transformation, the A/D that the signal become within the scope of the inner A/D incoming level of single-chip microcomputer can send into controller inside samples.Meanwhile, for obtaining response time when contactor closes, contactor both end voltage signal need be gathered to determine contactor closing moment accurately; For obtaining response time when contactor is opened, the current signal flowing through capacitor that is the current signal flowing through contactor need be gathered to determine that contactor opens the moment accurately.Meanwhile, the operating voltage of current ambient temperature and contactor is detected with the response time of Accurate Prediction contactor.

Threshold value=[0.7,0.8] is opened in step 4; Turn off threshold value=[0.93,0.95].

Embodiment two: present embodiment is described further execution mode one, the process obtaining power factor in step 3 is:

Step 31, by three-phase current signal i _a, i _b, i _cby formula

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=C_{3/2}\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

Be transformed to alpha-beta two-phase orthogonal coordinates and fasten transient current i _α, i _β;

In formula, C _3/2represent 3/2 transformation matrix of coordinates;

Step 32, alpha-beta two-phase orthogonal coordinates are fastened transient current i _α, i _βby formula

$\left[\begin{array}{c}p\\ q\end{array}\right]=\sqrt{\frac{3}{2}}{E}_m\left[\begin{array}{c}{i}_p\\ i_q\end{array}\right]=\sqrt{\frac{3}{2}}{E}_m\left[\begin{array}{cc}\sin \mathrm{\ωt}& -\cos \mathrm{\ωt}\\ -\cos \mathrm{\ωt}& -\sin \mathrm{\ωt}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]$

Obtain instantaneous active power p and instantaneous reactive power q;

In formula: E _mrepresent system voltage peak value;

Step 33, according to formula

$\mathrm{\α}=\frac{p}{\sqrt{p^2+q^2}}$

Obtain power factor α.

Embodiment three: present embodiment is described below in conjunction with Fig. 3, Fig. 4, Fig. 6, Fig. 7 and Fig. 8, present embodiment is described further execution mode one, control module in step 5 sends input compensation instruction, and the process making contactor perform closing operation by drive circuit is:

Step 51, determine to send moment immediate A phase voltage zero crossing with input compensation instruction;

Step 52, according to formula $t_{\mathrm{on}-j}={0.0002T}_j^3-{0.0002T}_j^2-{0.0981T}_j+148.7423+{\mathrm{\Δt}}_{j-1}$ Response cycle predicted value t opened by contactor when calculating jth time input contactor _on-j; J=1,2 ...

In formula: T _jambient temperature during input contactor secondary to jth; Δ t _j-1for contactor when this drops into contactor open response cycle actual value with last drop into contactor time contactor open the difference of response cycle predicted value; Make Δ t ₀=0;

Step 53, according to formula

$\left\{\begin{array}{c}{t}_{\mathrm{dA}-j}=n/2f-t_{\mathrm{on}-j}+8.33\\ t_{\mathrm{dB}-j}=n/2f-t_{\mathrm{on}-j}+5\\ t_{\mathrm{dC}-j}=n/2f-t_{\mathrm{on}-j}+1.67\end{array}\right.$

Obtain the minimum delay time t that contactor corresponding to three-phase compensation capacitor closes a floodgate _dA-j, t _dB-j, t _dC-j;

In formula: n is the minimum delay time t that contactor closes a floodgate _dA-j, t _dB-j, t _dC-jfor positive smallest positive integral value;

Step 54, the A phase voltage zero crossing determined with step 51 are for basic point, the minimum delay time that the contactor that the three-phase compensation capacitor obtained by step 53 is corresponding closes a floodgate carries out time delay, and the instruction then sent according to control module starts the closing operation of three-phase contactor.

To open response cycle actual value be after this closing operation completes to this contactor when dropping into contactor recorded in step 52, the numerical value measured by control module, is that control module issues instructions to contactor coil and powers on the experienced time.Adopt the circuit shown in Fig. 6 to carry out measurement can obtain.

When meeting switching condition needs to contactor action, gather and measure current temperature signal, call historical responses temporal database, the difference of response cycle predicted value opened by contactor when contactor when obtaining this cut-in and cut-off contactor opens response cycle actual value and last cut-in and cut-off contactor, and then calculates as ensureing the action delay time that switch operating passing zero needs; The fixed phase determined with the voltage and current signal zero passage detection at switch contact two ends again, for benchmark, after carrying out the time delay of certain hour, provides the switching instruction of system, ensures that the zero passage of contactor turns on and off.After contactor response, calculate single-chip microcomputer and send switching instruction to the time that contactor coil powers on as this contactor response cycle, stored in database, as the reference value of next contactor response cycle, circulation like this, moment can make optimal adjustment according to HVC field conditions, be response cycle from model-following control.

The formula that response cycle predicted value opened by contactor when calculating jth time input contactor described in present embodiment is applicable to ambient temperature between (-35 DEG C, 40 DEG C).When ambient temperature is positioned at outside (-35 DEG C, 40 DEG C), when ambient temperature is lower than-35 DEG C, response cycle predicted value adopts the value of-35 DEG C, ambient temperature higher than 40 DEG C and time, response cycle predicted value adopts the value of 40 DEG C.

Described response cycle prediction is the object based on synchronous switching, for synchronous switching is served, reaches operating passing zero the most accurately.After zero crossing being detected, by the response time of contactor, to determine that time of delay is to reach the accurate switching of next zero passage.Zero cross detection circuit is A phase voltage zero crossing is benchmark, when at t _amoment needs the ambient temperature determination delay time according to contactor work at present after monitoring the zero crossing nearest with reclosing command, and determines the true fixed phase point A of contactor actual act ₀because fixed phase point and the time difference of monitoring phase point are n/2f, therefore the switching order of three-phase compensation capacitor group is C phase-A phase-B phase, and be respectively 30 °, 90 ° and 150 ° with the phase angle difference of fixed phase point, the time delay concrete condition of input compensation as shown in Figure 4.The schematic diagram of the closing time that Fig. 7 and Fig. 8 provides respectively and opening time.

Embodiment four: present embodiment is described below in conjunction with Fig. 1, Fig. 2, Fig. 5, Figure 10 to Figure 15, present embodiment is described further execution mode one,

Control module in step 6 sends switching instruction, and the process making contactor perform sub-switching operation by drive circuit is:

Step 61, determine to send moment immediate A phase voltage zero crossing with switching instruction;

Step 62, according to formula

$t_{\mathrm{off}-k}={0.0001T}_k^4-{0.0003T}_k^3-0.0379T_k^2+{0.2871T}_k+21.0165+{{\mathrm{\Δt}}_{k-1}}^{\′}$

Calculate contactor turn-off response period forecasting value t during kth time cut-in and cut-off contactor _off-k; K=1,2 ...

In formula: T _kambient temperature during cut-in and cut-off contactor secondary to kth; Δ t _k-1' be the difference of contactor turn-off response period forecasting value when contactor turn-off response cycle actual value during this cut-in and cut-off contactor and last cut-in and cut-off contactor; Make Δ t ₀'=0;

Step 63, according to formula

$\left\{\begin{array}{c}{t}_{\mathrm{dA}-k}=n/2f-t_{\mathrm{on}-k}+8.33\\ t_{\mathrm{dB}-k}=n/2f-t_{\mathrm{on}-k}+5\\ t_{\mathrm{dC}-k}=n/2f-t_{\mathrm{on}-k}+1.67\end{array}\right.$

Obtain the minimum delay time t of contactor separating brake corresponding to three-phase compensation capacitor _dA-k, t _dB-k, t _dC-k;

Step 64, the A phase voltage zero crossing determined with step 61 are for basic point, the minimum delay time of the contactor separating brake that the three-phase compensation capacitor obtained by step 63 is corresponding carries out time delay, and the instruction then sent according to control module starts the sub-switching operation of three-phase contactor.

Contactor turn-off response cycle actual value during this cut-in and cut-off contactor recorded in step 62 is after this sub-switching operation completes, the numerical value measured by control module, is the time that control module issues instructions to contactor coil power-off and experiences.

The formula of contactor turn-off response period forecasting value when calculating jth time cut-in and cut-off contactor described in present embodiment is applicable to ambient temperature between (-35 DEG C, 40 DEG C).When ambient temperature is positioned at outside (-35 DEG C, 40 DEG C), when ambient temperature is lower than-35 DEG C, response cycle predicted value adopts the value of-35 DEG C, ambient temperature higher than 40 DEG C and time, response cycle predicted value adopts the value of 40 DEG C.

When contactor separating brake, according to the current ambient temperature of contactor to its response time t _off-kpredict, then determine with reference to zero crossing A ₀after, the separating brake order of three-phase compensation capacitor group is C phase-A phase-B phase, and be respectively 60 °, 120 ° and 180 ° with the phase angle difference of fixed phase point, the concrete condition of switching time delay is as shown in Figure 5.

Present embodiment gives a specific embodiment, by arranging HVC device shown in Fig. 2, closing and opening test is carried out by the method for the invention, then obtain the curved line relation of Figure 10 to Figure 15, can show that the random switching of contactor at non-zero crossing is to safeguarding that the stable operation of HVC device is very disadvantageous by Figure 10-Figure 15, and adopt the synchronous switching control mode designed by the present invention, predict based on the contactor response time, reference the most next for this response cycle warehouse-in is reached response cycle from model-following control, effectively can avoid the voltage current impact situation that contactor switching produces instantaneously.By contrasting twice switching effect of contactor, demonstrate the response time from model-following control strategy, can the action of control contactor time be engraved in its both end voltage electric current real zero-crossing point ± 1ms error range in, thus effectively avoid the switching moment issuable shock problem that shoves.

Claims (7)

1., based on the contactor switching reactive-load compensation method of response cycle prediction, adopt the mode of contactor switched capacitor to carry out reactive power compensation, it is characterized in that, the method comprises the following steps:

Step one, gather the three-phase voltage signal u of described contactor place electrical network _a, u _b, u _cwith three-phase current signal i _a, i _b, i _c, the zero passage detection signal of contactor both end voltage and the ambient temperature of device work at present, as detection signal;

Step 2, by Signal-regulated kinase, the detection signal that step one obtains to be processed, and the detection signal after process is sent into control module;

Step 3, in the control module, according to the detection signal after process, and adopts instantaneous reactive power theory to calculate the power factor of current system;

Step 4, judge the size of the power factor of current system, perform corresponding operating according to condition;

When power factor be less than or equal to open threshold value time, perform step 5;

When power factor is more than or equal to shutoff threshold value, perform step 6;

When power factor is in time opening threshold value and turn off between threshold value, keep laststate;

Step 5, control module send input compensation instruction, make contactor perform closing operation, carry out reactive power compensation by drive circuit; Return execution step 4;

Step 6, control module send switching instruction, make contactor perform sub-switching operation, then return execution step 3 by drive circuit.

2., according to claim 1 based on the contactor switching reactive-load compensation method of response cycle prediction, it is characterized in that, the process obtaining power factor in step 3 is:

Step 31, by three-phase current signal i _a, i _b, i _cby formula

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=C_{3/2}\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

Be transformed to alpha-beta two-phase orthogonal coordinates and fasten transient current i _α, i _β;

In formula, C _3/2represent 3/2 transformation matrix of coordinates;

Step 32, alpha-beta two-phase orthogonal coordinates are fastened transient current i _α, i _βby formula

$\left[\begin{array}{c}p\\ q\end{array}\right]=\sqrt{\frac{3}{2}}{E}_m\left[\begin{array}{c}{i}_p\\ i_q\end{array}\right]=\sqrt{\frac{3}{2}}{E}_m\left[\begin{array}{cc}\sin \mathrm{\ωt}& -\cos \mathrm{\ωt}\\ -\cos \mathrm{\ωt}& -\sin \mathrm{\ωt}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]$

Obtain instantaneous active power p and instantaneous reactive power q;

In formula: E _mrepresent system voltage peak value;

Step 33, according to formula

$\mathrm{\α}=\frac{p}{\sqrt{p^2+q^2}}$

Obtain power factor α.

3. according to claim 1 based on the contactor switching reactive-load compensation method of response cycle prediction, it is characterized in that, the control module in step 5 sends input compensation instruction, and the process making contactor perform closing operation by drive circuit is:

Step 51, determine to send moment immediate A phase voltage zero crossing with input compensation instruction;

Step 52, according to formula $t_{\mathrm{on}-j}=0.0002T_j^3-0.0002T_j^2-0.0981T_j+148.7423+\mathrm{\Δ}{t}_{j-1}$ Response cycle predicted value t opened by contactor when calculating jth time input contactor _on-j; J=1,2 ...

In formula: T _jambient temperature during input contactor secondary to jth; Δ t _j-1for contactor when this drops into contactor open response cycle actual value with last drop into contactor time contactor open the difference of response cycle predicted value; Make Δ t ₀=0;

Step 53, according to formula

$\left\{\begin{array}{c}{t}_{\mathrm{dA}-j}=n/2f-t_{\mathrm{on}-j}+8.33\\ t_{\mathrm{dB}-j}=n/2f-t_{\mathrm{on}-j}+5\\ t_{\mathrm{dC}-j}=n/2f-t_{\mathrm{on}-j}+1.67\end{array}\right.$

Obtain the minimum delay time t that contactor corresponding to three-phase compensation capacitor closes a floodgate _dA-j, t _dB-j, t _dC-j;

In formula: n is the minimum delay time t that contactor closes a floodgate _dA-j, t _dB-j, t _dC-jfor positive smallest positive integral value;

Step 54, the A phase voltage zero crossing determined with step 51 are for basic point, the minimum delay time that the contactor that the three-phase compensation capacitor obtained by step 53 is corresponding closes a floodgate carries out time delay, and the instruction then sent according to control module starts the closing operation of three-phase contactor.

4. according to claim 3 based on the contactor switching reactive-load compensation method of response cycle prediction, it is characterized in that, response cycle actual value opened by contactor during this input contactor is after this closing operation completes, the numerical value measured by control module is that control module issues instructions to contactor coil and powers on the experienced time.

5. according to claim 1 based on the contactor switching reactive-load compensation method of response cycle prediction, it is characterized in that, the control module in step 6 sends switching instruction, and the process making contactor perform sub-switching operation by drive circuit is:

Step 61, determine to send moment immediate A phase voltage zero crossing with switching instruction;

Step 62, according to formula

$t_{\mathrm{off}-k}=0.0001T_k^4+0.0003T_k^3-0.0379T_k^2+0.2871T_k+21.0165+\mathrm{\Δ}{t_{k-1}}^{\′}$

Calculate contactor turn-off response period forecasting value t during kth time cut-in and cut-off contactor _off-k; K=1,2 ...

In formula: T _kambient temperature during cut-in and cut-off contactor secondary to kth; Δ t _k-1' be the difference of contactor turn-off response period forecasting value when contactor turn-off response cycle actual value during this cut-in and cut-off contactor and last cut-in and cut-off contactor; Make Δ t ₀'=0;

Step 63, according to formula

$\left\{\begin{array}{c}{t}_{\mathrm{dA}-k}=n/2f-t_{\mathrm{on}-k}+8.33\\ t_{\mathrm{dB}-k}=n/2f-t_{\mathrm{on}-k}+5\\ t_{\mathrm{dC}-k}=n/2f-t_{\mathrm{on}-k}+1.67\end{array}\right.$

Obtain the minimum delay time t of contactor separating brake corresponding to three-phase compensation capacitor _dA-k, t _dB-k, t _dC-k;

Step 64, the A phase voltage zero crossing determined with step 61 are for basic point, the minimum delay time of the contactor separating brake that the three-phase compensation capacitor obtained by step 63 is corresponding carries out time delay, and the instruction then sent according to control module starts the sub-switching operation of three-phase contactor.

6. according to claim 5 based on the contactor switching reactive-load compensation method of response cycle prediction, it is characterized in that, contactor turn-off response cycle actual value during this cut-in and cut-off contactor is after this sub-switching operation completes, the numerical value measured by control module is the time that control module issues instructions to contactor coil power-off and experiences.

7., according to claim 1 based on the contactor switching reactive-load compensation method of response cycle prediction, it is characterized in that, open threshold value=[0.7,0.8]; Turn off threshold value=[0.93,0.95].