CN104124696B - power system voltage stabilization control method and system thereof - Google Patents

Abstract

The invention provides a kind of power system voltage stabilization control method and system, based on STATCOM (STATCOM) and MSC (mechanical type switched capacitor), the specified reactive capability of reactive power demand reference value, STATCOM and the MSC providing according to automatic voltage control system, determine the actual MSC group number that should drop into, and according to target component and described MSC group number, obtain the output reactive capability of STATCOM. If what automatic voltage control system was given is voltage reference value, also can controls and be translated into idle reference value by outer shroud PI, thereby carry out the distribution combination control of capacity. In the time that reactive power demand exceeds STATCOM and the total reactive capability scope of MSC array output, drop into greatest extent reactive compensation capacity, remaining reactive power demand will be provided by near Substation Reactive-power Compensation equipment. Can improve the stability that combination is controlled, improve the utilization ratio of STATCOM.

Description

Power system voltage stabilization control method and system thereof

Technical field

The present invention relates to the technical field of power system voltage stabilization control, particularly relate to a kind of power systemVoltage Stability Control method and system thereof.

Background technology

The a lot of Voltage Instabilities that occur in the world in recent years cause large area blackout, have brought huge warpJi loss and severe social influence, to power system safety and stability, operation has proposed stern challenge. At present,Installing reactive-load compensation equipment is one of important method improving Power System Voltage Stability. But, traditionalTaking mechanical type switched capacitor (english abbreviation MSC), as main, response speed is slower, is applicable to stable state in compensationControl; Along with the development of Power Electronic Technique and corresponding control technology, there is quick response, governing speedSTATCOM (english abbreviation STATCOM) is applied to actual electric network gradually to improve the transient state of systemVoltage stability, but the investment of STATCOM is relatively high. For reducing overall cost, improving cost performance,Effectively way is after both combinations, to carry out mixed compensation.

At present, conventional control method be MSC be subject to transformer station's REACTIVE POWER/VOLTAGE CONTROL or system-level automatic electric voltage-controlledSystem (english abbreviation AVC) is large according to the difference of idle output order or control bus voltage and reference voltageThe little REACTIVE POWER/VOLTAGE CONTROL order of carrying out, operation is moved back in the throwing that completes MSC; STATCOM adopts ratioExample integral controller (PI) is controlled, and utilizes controlled busbar voltage and reference voltage difference, regulates through PIWith after amplitude limit link, export reactive current, or directly carry out reactive power compensation according to AVC command request.Generally speaking, in current power system practical application, more consideration be both combination controls in the time of stable stateMethod processed is that the throwing of carrying out MSC based on stable state control target is moved back operation and regulated the electricity of STATCOMPressure/idle instruction. And STATCOM is as a kind of dynamic passive compensation equipment, although also studied for meritRate vibration suppresses, local voltage supports, but considers that cost is high, population size is limited, its practical application effectFruit is restricted. In addition on the one hand, for the situation of remote, the large volume transport of electric power, existence realityTransient Voltage Stability problem. Therefore, how to make full use of existing on a large scale arrange MSC and in recent years byThe STATCOM that step is applied, combines both to improve the transient voltage support energy of large-scale receiving end electrical networkPower, the collapse of prevention transient voltage is one of important technological challenge of current power industry.

Summary of the invention

For unsettled the asking of combination control of existing STATCOM and mechanical type switched capacitorTopic, the invention provides a kind of power system voltage stabilization control method, can improve STATCOM andThe stability that the combination of mechanical type switched capacitor is controlled, the utilization ratio of raising STATCOM.

A kind of power system voltage stabilization control method, based on STATCOM and mechanical type switching capacitanceDevice, comprises stable state control step:

A) obtain idle parameter, comprise the reactive power demand reference value Q that automatic voltage control system provides_L、The specified reactive capability Q of STATCOM in parallel on controlled bus_SN, the machinery of parallel connection on controlled busThe group of formula switched capacitor is counted N, and the specified reactive capability Q of each group mechanical type switched capacitor_C0；

B), according to described idle parameter, obtain the actual mechanical type opening-closing capacitor bank that should drop into and count n:

$n=\left\{\begin{array}{c}0,p<0\\ p,0\&le;p\&le;N\\ N,p>N\end{array}\right.;$

Wherein, $p=\&lsqb;\frac{Q_L+Q_{SN}}{Q_{C0}}\&rsqb;,$ For bracket function;

C) count n according to described idle parameter and the described actual mechanical type opening-closing capacitor bank that should drop into, obtainObtain the output reactive capability Q of STATCOM_S：

$Q_S=\left\{\begin{array}{c}max(Q_L-Q_C,-Q_{SN}),Q_L-Q_C<0\\ min(Q_L-Q_C,Q_{SN}),Q_L-Q_C\&GreaterEqual;0\end{array}\right.;$

Wherein, Q_CThe idle total capacity of the mechanical type switched capacitor output dropping into during for stable state, Q_C＝nQ_C0；

D) count n according to the described actual mechanical type opening-closing capacitor bank that should drop into, and described static synchronous benefitRepay the output reactive capability Q of device_S, control the mechanical type opening-closing capacitor bank number and the static synchroballistic that drop intoThe output reactive capability of device.

Power system voltage stabilization control method of the present invention, based on STATCOM and mechanical type switchingCapacitor, the reactive power demand reference value Q providing according to automatic voltage control system_L, static synchroballisticThe specified reactive capability Q of device and mechanical type switched capacitor_SN、Q_C0, determine the actual mechanical type switching that should drop intoCapacitor group is counted n, and according to described idle parameter and the described actual mechanical type switched capacitor that should drop intoGroup number n, the output reactive capability Q of acquisition STATCOM_S. If what automatic voltage control system was given isVoltage reference value, also can be controlled and be translated into idle reference value by outer shroud PI, thereby carries out dividing of capacityCombo is closed control. As reactive power demand Q_LExceed the total reactive capability Q of STATCOM and MSC array outputWhen scope, drop into greatest extent reactive compensation capacity, remaining reactive power demand will be by near transformer stationReactive-load compensation equipment provides. What if stand, level reactive power/voltage control or AVC system were given is voltage reference value,Control and be converted into reference to carrying out again above-mentioned coordinated allocation after reactive power with reference to voltage by outer shroud PI. CauseThis, can improve the stability that STATCOM and the combination of mechanical type switched capacitor are controlled, and improves quietThe only utilization ratio of synchronous compensator.

In one embodiment, step is controlled in the transient state enhancing that also comprises STATCOM:

E) obtain reference mode voltage V_j, wherein, described reference mode voltage V_jFor the voltage of our station bus orPerson's and electric pressure associated with our station is higher than the voltage of the maincenter bus of our station;

F) as described reference mode voltage V_jLower than critical voltage V_crTime exceed preset time t_cTime, obtainEquivalent voltage V:

V＝f(t)ΔQx；

Wherein, f (t) is the control function of hysteresis comparator output, $f\left(t\right)=\left\{\begin{array}{c}1,0\&le;t\&le;m\\ e^{-\frac{(t-m)}{\mathrm{\&tau;}}},t>m\end{array}\right.;$ M is reactive currentThe duration that amplitude limit strengthens, its value is according to the duration of STATCOM short-time overload operationDetermine the decay factor that τ is exponential function; Δ Q is the idle increment perunit value of STATCOM output,X is equivalent reactance parameter perunit value;

G) by described equivalent voltage V after lead-lag link and amplitude limit link with given controlled busReference voltage Vref stack, obtains the reference voltage V that transient state strengthens_ref′；

H) obtain controlled busbar voltage V_t, the reference voltage V that described transient state is strengthened_ref' with described controlled bus electricityPress V_tDifference input pid control module, obtain PID output signal;

I) according to the control function f (t) of described hysteresis comparator output, and described STATCOMThe reactive current amplitude limit numerical value I of conventional PI control_max, obtain reactive current enhancing value I_max′：

I_max'＝I_max(1+Kf(t))；

Wherein, the gain multiple that K is control function;

By described PID output signal and described reactive current enhancing value I_max' stack, output STATCOMTransient state strengthen reactive current.

Reactive power when power system voltage stabilization control method of the present invention can realize transient state with lower costAdjusting rapidly, continuously, improve Enhancement of Transient Voltage Stability.

Corresponding with described power system voltage stabilization control method, the present invention also provides a kind of power system electricityPress stabilizing control system, can improve the steady of STATCOM and mechanical type switched capacitor combination controlQualitative, the utilization ratio of raising STATCOM.

A kind of power system voltage stabilization control system, based on STATCOM and mechanical type switching capacitanceDevice, it comprises: stable state control module, described stable state control module comprises idle parameter acquisition module, electric capacityDevice switching computing module, compensator reactive capability computing module and stable state control module;

Described idle parameter acquisition module, for obtaining idle parameter, comprises that automatic voltage control system providesReactive power demand reference value Q_L, the specified reactive capability of STATCOM in parallel on controlled busQ_SN, on controlled bus, the group of mechanical type switched capacitor in parallel is counted N, and each group mechanical type switching electricityThe specified reactive capability Q of container_C0；

Described capacitor switching computing module, for according to described idle parameter, obtains the actual machine that should drop intoTool formula opening-closing capacitor bank is counted n:

$n=\left\{\begin{array}{c}0,p<0\\ p,0\&le;p\&le;N\\ N,p>N\end{array}\right.;$

Wherein, $p=\&lsqb;\frac{Q_L+Q_{SN}}{Q_{C0}}\&rsqb;,$ For bracket function;

Described compensator reactive capability computing module, for according to described idle parameter and described actual should throwingThe mechanical type opening-closing capacitor bank entering is counted n, obtains the output reactive capability Q of STATCOM_S：

$Q_S=\left\{\begin{array}{c}max(Q_L-Q_C,-Q_{SN}),Q_L-Q_C<0\\ min(Q_L-Q_C,Q_{SN}),Q_L-Q_C\&GreaterEqual;0\end{array}\right.;$

Wherein, Q_CThe idle total capacity of the mechanical type switched capacitor output dropping into during for stable state, Q_C＝nQ_C0；

Described stable state control module, for counting n according to the described actual mechanical type opening-closing capacitor bank that should drop into,And the output reactive capability Q of described STATCOM_S, control the mechanical type opening-closing capacitor bank dropping intoThe output reactive capability of number and STATCOM.

In one embodiment, also comprise the transient state enhancing control module of STATCOM, described transient stateStrengthening control module comprises: reference voltage transient state strengthens module, pid control module and reactive current amplitude limitStrengthen module;

Described reference voltage transient state strengthens module and comprises: node voltage module, equivalent voltage module, stagnant in advanceMetasomite and amplitude limit link;

Described node voltage module, for obtaining reference mode voltage V_j, wherein, described reference mode voltage V_jFor the voltage of our station bus or and electric pressure associated with our station are higher than the voltage of the maincenter bus of our station;

Described equivalent voltage module, for working as described reference mode voltage V_jLower than critical voltage V_crTime superCross preset time t_cTime, obtain equivalent voltage V:

V＝f(t)ΔQx；

Wherein, f (t) is the control function of hysteresis comparator output, $f\left(t\right)=\left\{\begin{array}{c}1,0\&le;t\&le;m\\ e^{-\frac{(t-m)}{\mathrm{\&tau;}}},t>m\end{array}\right.;$ M is reactive currentThe duration that amplitude limit strengthens, its value is according to the duration of STATCOM short-time overload operationDetermine the decay factor that τ is exponential function; Δ Q is the idle increment perunit value of STATCOM output,X is equivalent reactance parameter perunit value;

Described equivalent voltage V after lead-lag link and amplitude limit link with given controlled bus referenceVoltage Vref stack, obtains the reference voltage V that transient state strengthens_ref' after, the reference voltage V that described transient state strengthens_ref' withDescribed controlled busbar voltage V_tDifference input described pid control module, obtain PID output signal;

Described reactive current amplitude limit strengthens the control function f (t) of module for exporting according to described hysteresis comparator,And the reactive current amplitude limit numerical value I of the conventional PI control of described STATCOM_max, obtain reactive currentEnhancing value I_max′：

I_max'＝I_max(1+Kf(t))；

Wherein, the gain multiple that K is control function;

Described PID output signal and described reactive current enhancing value I_max' stack, output STATCOMTransient state strengthens reactive current.

Brief description of the drawings

Fig. 1 is a kind of applied environment figure of power system voltage stabilization control method of the present invention;

Fig. 2 is the schematic flow sheet of power system voltage stabilization control method of the present invention;

Fig. 3 is the classical PI control principle schematic diagram of traditional STATCOM;

Fig. 4 is that the transient state of STATCOM in power system voltage stabilization control method of the present invention strengthens controlA kind of implementation schematic diagram of system;

Fig. 5 is stable state control and transient state enhancing control combination in power system voltage stabilization control method of the present inventionA kind of implementation schematic diagram of application.

Detailed description of the invention

Power system voltage stabilization control method of the present invention can be applicable in power system as shown in Figure 1,In described power system, STATCOM (STATCOM) and multiple mechanical type switched capacitor(MSC) be connected in parallel on same bus, thereby be idle merit while accelerating large disturbance Down Highway voltage rapid fluctuationResponse speed and the dynamic range of rate compensation are reasonably allocated to STATCOM by System Reactive Power demand in the time of stable stateOn MSC.

Refer to Fig. 2, Fig. 2 is the schematic flow sheet of power system voltage stabilization control method of the present invention.

Described power system voltage stabilization control method, comprising:

A kind of power system voltage stabilization control method, based on STATCOM and mechanical type switching capacitanceDevice, comprises stable state control step:

A) obtain idle parameter, comprise the reactive power demand reference value Q that automatic voltage control system provides_L、The specified reactive capability Q of STATCOM in parallel on controlled bus_SN, the machinery of parallel connection on controlled busThe group of formula switched capacitor is counted N, and the specified reactive capability Q of each group mechanical type switched capacitor_C0；

B), according to described idle parameter, obtain the actual mechanical type opening-closing capacitor bank that should drop into and count n:

$n=\left\{\begin{array}{c}0,p<0\\ p,0\&le;p\&le;N\\ N,p>N\end{array}\right.;$

Wherein, $p=\&lsqb;\frac{Q_L+Q_{SN}}{Q_{C0}}\&rsqb;,$ For bracket function;

C) count n according to described target component and the described actual mechanical type opening-closing capacitor bank that should drop into, obtainObtain the output reactive capability Q of STATCOM_S：

$Q_S=\left\{\begin{array}{c}max(Q_L-Q_C,-Q_{SN}),Q_L-Q_C<0\\ min(Q_L-Q_C,Q_{SN}),Q_L-Q_C\&GreaterEqual;0\end{array}\right.;$

Wherein, Q_CThe idle total capacity of the mechanical type switched capacitor output dropping into during for stable state, Q_C＝nQ_C0；

D) count n according to the described actual mechanical type opening-closing capacitor bank that should drop into, and described static synchronous benefitRepay the output reactive capability Q of device_S, control the mechanical type opening-closing capacitor bank number and the static synchroballistic that drop intoThe output reactive capability of device.

Wherein, for step a), obtain idle parameter;

The present embodiment, for clearly demonstrating power system voltage stabilization control method of the present invention, is defined as follows severalKey variables: Q_LIn order to stand, level reactive power/voltage control or system-level automatism voltage control (english abbreviation AVC) are carriedThe reactive power demand reference value of confession; Q is the total reactive capability of STATCOM and MSC array output; Q_SFor the reactive capability of STATCOM output; Q_CFor the idle total capacity of the MSC output that drops into; Q_SNForThe specified reactive capability of STATCOM; Q_C0It is the specified reactive capability of one group of MSC; Generally there is Q_C0＜Q_SN。

Suppose that it is Q that certain transformer station is provided with rated capacity_SNSTATCOM and N group rated capacity be Q_C0MSC, the output area of each idle variable is shown below:

Q_S∈[-Q_SN,Q_SN]

Q_C∈[0,NQ_C0]

Q∈[-Q_SN,NQ_C0+Q_SN]。

Step a) in, the idle parameter of obtaining comprises the reactive power demand that automatic voltage control system providesReference value Q_L, the specified reactive capability Q of STATCOM in parallel on controlled bus_SN, on controlled busThe group of mechanical type switched capacitor in parallel is counted N, and each group mechanical type switched capacitor is specified idleCapacity Q_C0。

For step b), STATCOM and MSC coordinate the idle concrete distribution measure of output withThe capacity configuration of STATCOM, MSC and Q_LAll relevant. Therefore defining intermediate variable p is shown below:

$p=\&lsqb;\frac{Q_L+Q_{SN}}{Q_{C0}}\&rsqb;$

Wherein, p is bracket function, and it is defined as and is no more than real numberMaximum integer.

In STATCOM and the control of MSC combination stable state, what control output is the MSC group number that should drop intoN and STATCOM without work output Q_S. Therefore the MSC group number dropping into need be limited between 0～N,Concrete expression formula is as follows:

$n=\left\{\begin{array}{c}0,p<0\\ p,0\&le;p\&le;N\\ N,p>N\end{array}\right.$

Because the capacity of every group of MSC is certain, be Q_C0, the MSC total capacity therefore dropping into when stable state representsFormula is:

Q_C＝nQ_C0。

For step c), in the control of combination stable state, the output reactive capability of STATCOM is by reactive requirement Q_LWithAnd the capacity Q of MSC input_CCommon decision, exceeds formula Q but work as capacity_SScope time will carry out saturated output,Expression is as follows:

$Q_S=\left\{\begin{array}{c}max(Q_L-Q_C,-Q_{SN}),Q_L-Q_C<0\\ min(Q_L-Q_C,Q_{SN}),Q_L-Q_C\&GreaterEqual;0\end{array}\right.$

As reactive power demand Q_LWhile exceeding STATCOM and the total reactive capability Q of MSC array output scope,Our station drops into reactive compensation capacity to greatest extent, and remaining reactive power demand will be idle by near transformer stationCompensation equipment provides.

Above-mentioned is according to reactive power demand reference value Q_LThe distribution measure of carrying out. The level reactive power/voltage control if standOr AVC system given be voltage reference value, by outer shroud PI control be converted into reference to nothing with reference to voltageAfter merit power, carry out again above-mentioned coordinated allocation.

For steps d) count n according to the described actual mechanical type opening-closing capacitor bank that should drop into, and described quietThe only output reactive capability Q of synchronous compensator_S, the mechanical type opening-closing capacitor bank number that control drops into and staticThe output reactive capability of synchronous compensator.

Power system voltage stabilization control method of the present invention is based on STATCOM and mechanical type switching electricityContainer, the reactive power demand reference value Q providing according to automatic voltage control system_L, STATCOMSpecified reactive capability Q with mechanical type switched capacitor_SN、Q_C0, determine the actual mechanical type switching electricity that should drop intoContainer group is counted n, and according to described target component and the described actual mechanical type opening-closing capacitor bank that should drop intoNumber n, the output reactive capability Q of acquisition STATCOM_S. If what automatic voltage control system was given is electricityPress reference value, also can control and be translated into idle reference value by outer shroud PI, thereby carry out the distribution of capacityCombination is controlled. As reactive power demand Q_LExceed STATCOM and the total reactive capability Q of MSC array output modelWhile enclosing, drop into greatest extent reactive compensation capacity, remaining reactive power demand will by near transformer station withoutMerit compensation equipment provides. What if stand, level reactive power/voltage control or AVC system were given is voltage reference value, logicalCrossing outer shroud PI control is converted into reference to carrying out above-mentioned coordinated allocation after reactive power with reference to voltage again. Therefore,Can improve the stability that STATCOM and the combination of mechanical type switched capacitor are controlled, improve static sameThe utilization ratio of step compensator.

In one embodiment, power system voltage stabilization control method of the present invention also comprises static synchronous benefitThe transient state of repaying device strengthens controls step:

E) obtain reference mode voltage V_j, wherein, described reference mode voltage V_jFor the voltage of our station bus orPerson's and electric pressure associated with our station is higher than the voltage of the maincenter bus of our station;

F) as described reference mode voltage V_jLower than critical voltage V_crTime exceed preset time t_cTime, obtainEquivalent voltage V:

V＝f(t)ΔQx；

Wherein, f (t) is the control function of hysteresis comparator output, $f\left(t\right)=\left\{\begin{array}{c}1,0\&le;t\&le;m\\ e^{-\frac{(t-m)}{\mathrm{\&tau;}}},t>m\end{array}\right.;$ M is reactive currentThe duration that amplitude limit strengthens, its value is according to the duration of STATCOM short-time overload operationDetermine the decay factor that τ is exponential function; Δ Q is the idle increment perunit value of STATCOM output,X is equivalent reactance parameter perunit value;

G) by described equivalent voltage V after lead-lag link and amplitude limit link with given controlled busReference voltage Vref stack, obtains the reference voltage V that transient state strengthens_ref′；

H) obtain controlled busbar voltage V_t, the reference voltage V that described transient state is strengthened_ref' with described controlled bus electricityPress V_tDifference input pid control module, obtain PID output signal;

I) according to the control function f (t) of described hysteresis comparator output, and described STATCOMThe reactive current amplitude limit numerical value I of conventional PI control_max, obtain reactive current enhancing value I_max′：

I_max'＝I_max(1+Kf(t))；

Wherein, the gain multiple that K is control function;

By described PID output signal and described reactive current enhancing value I_max' stack, output STATCOMTransient state strengthen reactive current.

Because the response time of MSC is longer, can not bear transient state and regulate task, the main task of transient processBe the idle output of controlling STATCOM, can bring into play to greatest extent its transient voltage enabling capabilities,The reactive power capacity of output system demand, the Enhancement of Transient Voltage Stability of raising system. Therefore the present invention proposesPower system voltage stabilization control method be at traditional STATCOM warp to STATCOM control methodAllusion quotation PI controls on (as shown in Figure 3) basis and improves and form, and it can pass through structure as shown in Figure 4 realizes,The transient state of STATCOM strengthens control and is mainly divided into three parts, and reference voltage transient state strengthens, improves PID and adjustsJoint and reactive current amplitude limit strengthen.

Wherein, for step e), the input reference voltage of the PID controlling unit in the present invention is controlled motherLine voltage V_tOn basis, consider the voltage V of reference mode_jRepair with the reactive power of the current output of STATCOMOrder and obtain. Therefore obtain in this step reference mode voltage V_j. The traditional control method of STATCOM is only examinedConsidered the impact of controlled busbar voltage, and the present invention increases reference mode voltage V_jImpact, wherein node jChoose the concrete condition that can transformer station be installed according to STATCOM select in our station bus or this region withThe maincenter bus of the more voltage levels that our station relevance is stronger.

For step f), as shown in Figure 4, as reference mode voltage V_jLower than critical voltage V_crTime superCross preset time t_cSecond time, through hysteresis comparator output control function f (t), specific as follows shown in:

$f\left(t\right)=\left\{\begin{array}{c}1,0\&le;t\&le;m\\ e^{-\frac{(t-m)}{\mathrm{\&tau;}}},t>m\end{array}\right.$

Wherein, m is the duration that reactive current amplitude limit strengthens, and its value is according to STATCOM mistake in short-termThe duration of carrying row is determined, the decay factor that τ is exponential function. Described critical voltage V_crBe preferably and getValue 0.9pu, taking rating average voltage as benchmark, described preset time t_cBe preferably 10ms.

In addition the reference voltage transient state enhancing link that, the present invention proposes has also been considered the output nothing of STATCOMThe impact of merit power increment, equivalent voltage V is amid all these factors output as:

V＝f(t)ΔQx

In formula, f (t) is above-mentioned control function, and Δ Q is the idle increment perunit value of STATCOM output, xFor equivalent reactance parameter perunit value.

For step g), the V after the reference voltage transient state that the present invention proposes strengthens_ref' be that equivalent voltage V is through superAfter front delay component, amplitude limit, form with given controlled bus reference voltage Vref stack. Consider that bus is temporaryState upper voltage limit, be preferably ± 0.2pu of amplitude limit value.

Control and in model, only adopt compared with controlled busbar voltage with the classical PI of traditional STATCOM, the present inventionIn the power system voltage stabilization control method proposing, STATCOM reference voltage transient state strengthens has considered transient stateIn process, the feedback of reference mode voltage, the idle output increment of STATCOM, has improved in transient processThe transient voltage reference amplitude of STATCOM, makes it export more reactive power, is conducive to improve transient state electricityPress enabling capabilities.

For step h), obtain controlled busbar voltage V_t, the reference voltage V that described transient state is strengthened_ref' with described inControlled busbar voltage V_tDifference input pid control module, obtain PID output signal;

The present invention controls on basis and has increased differentiation element at traditional PI, forms PID and controls. This PID ringJoint takes full advantage of the load regulation function of differential, makes STATCOM have dynamic responding speed faster.Concrete setting parameter can be according to the capacity of real system STATCOM and MSC and access point bus shortThe parameters such as appearance of a street amount design.

For step I), the present invention makes full use of the short-time overload capacity of STATCOM, traditional idleCurrent limit link strengthens on basis, makes STATCOM reactive current amplitude limit in transient processWider, can provide than the more reactive power of traditional control method, improve its transient voltage enabling capabilities.

The control function f (t) that concrete amplitude limit enhancement measures has utilized reference mode to export in transient process, warpAfter crossing K gain-adjusted, transient state reactive current amplitude limit is strengthened as original 1+Kf (t) times, reactive current amplitude limit increasesNew value I after strong_max' can be expressed as:

I_max'＝I_max(1+Kf(t))

Wherein, I_maxFor the reactive current amplitude limit numerical value of the conventional PI control of described STATCOM, KFor the gain multiple of control function, to choose according to the short-time overload capacity of STATCOM, its value exists conventionallyIn 0.2～1 scope. Because f (t) is piecewise function, after lasting m second its functional value by exponential form decay,Therefore reactive current amplitude limit strengthens the front m second that mainly concentrates on transient process, after this will decay to gradually traditionReactive current amplitude limit value. This and actual electric network are wished STATCOM Quick in the time there is large disturbance accidentThe demand supporting for transient voltage matches.

By described PID output signal and described reactive current enhancing value I_max' stack, just can obtain static synchronous benefitThe transient state of repaying device strengthens reactive current.

Reactive power when power system voltage stabilization control method of the present invention can realize transient state with lower costAdjusting rapidly, continuously, improve Enhancement of Transient Voltage Stability.

In one embodiment, power system voltage stabilization control method of the present invention is further comprising the steps of:

By the output reactive capability Q of the STATCOM obtaining in above-mentioned steps d_SAs transient processThe reactive power reference qref Q of STATCOM_Sref, and by described reactive power reference qref Q_SrefWith its actual measurementIdle output Q_SrealDifference after integration with controlled bus reference voltage V_refStack, acting in conjunction is in instituteThe transient state of stating STATCOM strengthens to be controlled.

When the control of combination stable state and the STATCOM transient state of described STATCOM and MSC strengthen control simultaneouslyWhen use, concrete connection control system can be as shown in Figure 5. In accompanying drawing to combination stable state control andThe transient state of STATCOM strengthens to control and encapsulates, so as more clearly to check stable state and transient state control mutualBetween annexation.

The combination stable state control of STATCOM and MSC is according to the given reference reactive power Q of AVC system_LGiveThe MSC group number n that surely need to put into operation and the idle output Q of STATCOM_S. To combine stable state controlGiven STATCOM is without work output Q_SAs the reactive power output reference value Q of its transient process_Sref,Meet: Q_Sref＝Q_S。

As shown in Figure 5, the reactive power reference qref Q of STATCOM_SrefIdle output Q with its actual measurement_Sreal'sDeviation after integration with controlled bus reference voltage V_ref' (can be set by the user, or get default value 1.0pu) is foldedAdd, acting in conjunction strengthens and controls in STATCOM transient state, thereby by stable state control and transient state control effectivelyCouple together.

In real system, can make one is specifically designed to and realizes that STATCOM and MSC combination coordinates to controlSwitch board, the annexation of stable state control and transient state control and the parameter demand of each link are as shown in Figure 5.The input signal of switch board comprises the controlled busbar voltage V of STATCOM and MSC_t, AVC system is givenReactive requirement reference value Q_L, reference mode busbar voltage V_j, parameter comprise in station the MSC that installs organize number N andEvery pool-size Q_C0, STATCOM rated capacity Q_SN, equivalent reactance parameter x, controlled bus reference voltage V_ref′、The duration m that reactive current amplitude limit strengthens, the decay factor τ of control function Exponential function, gain multipleK and pid control parameter, be output as the reactive current size I of STATCOM_S. Switch board internal algorithm andCircuit can be realized by DSP, and wherein pid control parameter setting can be according to real system STATCOM and MSCThe parameter such as capacity and the capacity of short circuit of access point bus design.

Corresponding with described power system voltage stabilization control method, the present invention also provides a kind of power system electricityPress stabilizing control system, can improve the steady of STATCOM and mechanical type switched capacitor combination controlQualitative, the utilization ratio of raising STATCOM.

A kind of power system voltage stabilization control system, based on STATCOM and mechanical type switching capacitanceDevice, it comprises: stable state control module, described stable state control module comprises idle parameter acquisition module, electric capacityDevice switching computing module, compensator reactive capability computing module and stable state control module;

Described idle parameter acquisition module, for obtaining idle parameter, comprises that automatic voltage control system providesReactive power demand reference value Q_L, the specified reactive capability of STATCOM in parallel on controlled busQ_SN, on controlled bus, the group of mechanical type switched capacitor in parallel is counted N, and each group mechanical type switching electricityThe specified reactive capability Q of container_C0；

Described capacitor switching computing module, for according to described idle parameter, obtains the actual machine that should drop intoTool formula opening-closing capacitor bank is counted n:

$n=\left\{\begin{array}{c}0,p<0\\ p,0\&le;p\&le;N\\ N,p>N\end{array}\right.;$

Wherein, $p=\&lsqb;\frac{Q_L+Q_{SN}}{Q_{C0}}\&rsqb;,$ For bracket function;

Described compensator reactive capability computing module, for according to described target component and described actual should throwingThe mechanical type opening-closing capacitor bank entering is counted n, obtains the output reactive capability Q of STATCOM_S：

$Q_S=\left\{\begin{array}{c}max(Q_L-Q_C,-Q_{SN}),Q_L-Q_C<0\\ min(Q_L-Q_C,Q_{SN}),Q_L-Q_C\&GreaterEqual;0\end{array}\right.;$

Wherein, Q_CThe idle total capacity of the mechanical type switched capacitor output dropping into during for stable state, Q_C＝nQ_C0；

Described stable state control module, for counting n according to the described actual mechanical type opening-closing capacitor bank that should drop into,And the output reactive capability Q of described STATCOM_S, control the mechanical type opening-closing capacitor bank dropping intoThe output reactive capability of number and STATCOM.

In one embodiment, also comprise the transient state enhancing control module of STATCOM, described transient stateStrengthening control module comprises: reference voltage transient state strengthens module, pid control module and reactive current amplitude limitStrengthen module;

Described reference voltage transient state strengthens module and comprises: node voltage module, equivalent voltage module, stagnant in advanceMetasomite and amplitude limit link;

Described node voltage module, for obtaining reference mode voltage V_j, wherein, described reference mode voltage V_jFor the voltage of our station bus or and electric pressure associated with our station are higher than the voltage of the maincenter bus of our station;

Described equivalent voltage module, for working as described reference mode voltage V_jLower than critical voltage V_crTime superCross preset time t_cTime, obtain equivalent voltage V:

V＝f(t)ΔQx；

Wherein, f (t) is the control function of hysteresis comparator output, $f\left(t\right)=\left\{\begin{array}{c}1,0\&le;t\&le;m\\ e^{-\frac{(t-m)}{\mathrm{\&tau;}}},t>m\end{array}\right.;$ M is reactive currentThe duration that amplitude limit strengthens, its value is according to the duration of STATCOM short-time overload operationDetermine the decay factor that τ is exponential function; Δ Q is the idle increment perunit value of STATCOM output,X is equivalent reactance parameter perunit value;

Described equivalent voltage V after lead-lag link and amplitude limit link with given controlled bus referenceVoltage Vref stack, obtains the reference voltage V that transient state strengthens_ref' after, the reference voltage V that described transient state strengthens_ref' withDescribed controlled busbar voltage V_tDifference input described pid control module, obtain PID output signal;

Described reactive current amplitude limit strengthens the control function f (t) of module for exporting according to described hysteresis comparator,And the reactive current amplitude limit numerical value I of the conventional PI control of described STATCOM_max, obtain reactive currentEnhancing value I_max′：

I_max'＝I_max(1+Kf(t))；

Wherein, the gain multiple that K is control function;

Described PID output signal and described reactive current enhancing value I_max' stack, output STATCOMTransient state strengthens reactive current.

The output of the STATCOM that in one embodiment, described stable state control module obtains is without power capacityAmount Q_SAs the reactive power reference qref Q of the STATCOM of transient process_Sref, described reactive power referenceValue Q_SrefIdle output Q with its actual measurement_SrealDifference after integration with controlled bus reference voltage V_refStack,Acting in conjunction strengthens and controls in the transient state of described STATCOM.

Power system voltage stabilization control system of the present invention and power system voltage stabilization controlling party of the present inventionMethod is corresponding, again repeats no longer one by one.

Power system voltage stabilization control method and system that the present invention proposes, fully combine MSC low costWith the STATCOM characteristic of response fast, there is following advantage:

(1) overall cost is low, and cost performance is high;

(2) the capacitor group dropping into and STATCOM can meet system-level reactive requirement and maintain bus steadyState voltage levvl;

(3) the reference voltage transient state of STATCOM strengthen link considered reference mode voltage andThe impact of STATCOM output reactive power increment, has improved the transient state electricity of STATCOM in transient processPress reference amplitude, make it export more reactive power, be conducive to improve transient voltage enabling capabilities;

(4) introducing of differential differentiation element, greatly improves the dynamic responding speed of STATCOM;

(5) reactive current amplitude limit strengthens link, takes full advantage of the short-time overload capacity of STATCOM, makesIt can export more reactive power to improve system transient modelling voltage stability in transient process.

The present invention, by the combination control of STATCOM and MSC, gives full play to MSC low price,The advantages such as STATCOM fast response time, continuously smooth regulate, short-time overload capacity is strong, with optimum combination controlMode processed has improved the Enhancement of Transient Voltage Stability of system under large disturbance form.

The above embodiment has only expressed several embodiment of the present invention, and it describes comparatively concrete and detailed,But can not therefore be interpreted as the restriction to the scope of the claims of the present invention. It should be pointed out that for this areaThose of ordinary skill, without departing from the inventive concept of the premise, can also make some distortion andImprove, these all belong to protection scope of the present invention. Therefore, the protection domain of patent of the present invention should be with appendedClaim is as the criterion.

Claims (4)

1. a power system voltage stabilization control method, based on STATCOM and mechanical type switching electricityContainer, is characterized in that, comprises stable state control step:

A) obtain idle parameter, comprise the reactive power demand reference value Q that automatic voltage control system provides_L、The specified reactive capability Q of STATCOM in parallel on controlled bus_SN, the machinery of parallel connection on controlled busThe group of formula switched capacitor is counted N, and the specified reactive capability Q of each group mechanical type switched capacitor_C0；

B), according to described idle parameter, obtain the actual mechanical type opening-closing capacitor bank that should drop into and count n:

$n=\left\{\begin{array}{c}0,p<0\\ p,0\&le;p\&le;N\\ N,p>N\end{array}\right.;$

Wherein,For bracket function;

C) count n according to described idle parameter and the described actual mechanical type opening-closing capacitor bank that should drop into, obtainObtain the output reactive capability Q of STATCOM_S：

$Q_S=\left\{\begin{array}{c}max(Q_L-Q_C,-Q_{SN}),Q_L-Q_C<0\\ min(Q_L-Q_C,Q_{SN}),Q_L-Q_C\&GreaterEqual;0\end{array}\right.;$

Wherein, Q_CThe idle total capacity of the mechanical type switched capacitor output dropping into during for stable state, Q_C＝nQ_C0；

D) count n according to the described actual mechanical type opening-closing capacitor bank that should drop into, and described static synchronous benefitRepay the output reactive capability Q of device_S, control the mechanical type opening-closing capacitor bank number and the static synchroballistic that drop intoThe output reactive capability of device;

E) obtain reference mode voltage V_j, wherein, described reference mode voltage V_jFor the voltage of our station bus orPerson's and electric pressure associated with our station is higher than the voltage of the maincenter bus of our station;

F) as described reference mode voltage V_jLower than critical voltage V_crTime exceed preset time t_cTime, obtainEquivalent voltage V:

V＝f(t)ΔQx；

Wherein, f (t) is the control function of hysteresis comparator output, $f\left(t\right)=\left\{\begin{array}{c}1,0\&le;t\&le;m\\ e^{-\frac{(t-m)}{\mathrm{\&tau;}}},t>m\end{array}\right.;$ M is reactive currentThe duration that amplitude limit strengthens, its value is according to the duration of STATCOM short-time overload operationDetermine the decay factor that τ is exponential function; Δ Q is the idle increment perunit value of STATCOM output,X is equivalent reactance parameter perunit value;

G) by described equivalent voltage V after lead-lag link and amplitude limit link with given controlled busReference voltage Vref stack, obtains the reference voltage V that transient state strengthens_ref′；

H) obtain controlled busbar voltage V_t, the reference voltage V that described transient state is strengthened_ref' with described controlled bus electricityPress V_tDifference input pid control module, obtain PID output signal;

I) according to the control function f (t) of described hysteresis comparator output, and described STATCOMThe reactive current amplitude limit numerical value I of conventional PI control_max, obtain reactive current enhancing value I_max′：

I_max'＝I_max(1+Kf(t))；

Wherein, the gain multiple that K is control function;

By described PID output signal and described reactive current enhancing value I_max' stack, output STATCOMTransient state strengthen reactive current.

2. power system voltage stabilization control method as claimed in claim 1, is characterized in that, also comprisesFollowing steps:

By the output reactive capability Q of the STATCOM obtaining in above-mentioned steps d_SAs transient processThe reactive power reference qref Q of STATCOM_Sref, and by described reactive power reference qref Q_SrefWith its actual measurementIdle output Q_SrealDifference after integration with controlled bus reference voltage V_refStack, acting in conjunction is in instituteThe transient state of stating STATCOM strengthens to be controlled.

3. a power system voltage stabilization control system, is characterized in that, based on STATCOM andMechanical type switched capacitor, it comprises: stable state control module, described stable state control module comprises idle parameterAcquisition module, capacitor switching computing module, compensator reactive capability computing module and stable state control module;

Described idle parameter acquisition module, for obtaining idle parameter, comprises that automatic voltage control system providesReactive power demand reference value Q_L, the specified reactive capability of STATCOM in parallel on controlled bus Q_SN, on controlled bus, the group of mechanical type switched capacitor in parallel is counted N, and each group mechanical type switching electricityThe specified reactive capability Q of container_C0；

Described capacitor switching computing module, for according to described idle parameter, obtains the actual machine that should drop intoTool formula opening-closing capacitor bank is counted n:

$n=\left\{\begin{array}{c}0,p<0\\ p,0\&le;p\&le;N\\ N,p>N\end{array}\right.;$

Wherein,For bracket function;

Described compensator reactive capability computing module, for according to described idle parameter and described actual should throwingThe mechanical type opening-closing capacitor bank entering is counted n, obtains the output reactive capability Q of STATCOM_S：

$Q_S=\left\{\begin{array}{c}max(Q_L-Q_C,-Q_{SN}),Q_L-Q_C<0\\ min(Q_L-Q_C,Q_{SN}),Q_L-Q_C\&GreaterEqual;0\end{array}\right.;$

Wherein, Q_CThe idle total capacity of the mechanical type switched capacitor output dropping into during for stable state, Q_C＝nQ_C0；

Described stable state control module, for counting n according to the described actual mechanical type opening-closing capacitor bank that should drop into,And the output reactive capability Q of described STATCOM_S, control the mechanical type opening-closing capacitor bank dropping intoThe output reactive capability of number and STATCOM;

It is single that described power system voltage stabilization control system also comprises that the transient state of STATCOM strengthens controlUnit, described transient state strengthens control module and comprises: reference voltage transient state strengthen module, pid control module andReactive current amplitude limit strengthens module;

Described reference voltage transient state strengthens module and comprises: node voltage module, equivalent voltage module, stagnant in advanceMetasomite and amplitude limit link;

Described node voltage module, for obtaining reference mode voltage V_j, wherein, described reference mode voltage V_jFor the voltage of our station bus or and electric pressure associated with our station are higher than the voltage of the maincenter bus of our station;

Described equivalent voltage module, for working as described reference mode voltage V_jLower than critical voltage V_crTime superCross preset time t_cTime, obtain equivalent voltage V:

V＝f(t)ΔQx；

Wherein, f (t) is the control function of hysteresis comparator output,M is reactive currentThe duration that amplitude limit strengthens, its value is according to the duration of STATCOM short-time overload operationDetermine the decay factor that τ is exponential function; Δ Q is the idle increment perunit value of STATCOM output,X is equivalent reactance parameter perunit value;

Described equivalent voltage V after lead-lag link and amplitude limit link with given controlled bus referenceVoltage Vref stack, obtains the reference voltage V that transient state strengthens_ref' after, the reference voltage V that described transient state strengthens_ref' withControlled busbar voltage V_tDifference input described pid control module, obtain PID output signal;

Described reactive current amplitude limit strengthens the control function f (t) of module for exporting according to described hysteresis comparator,And the reactive current amplitude limit numerical value I of the conventional PI control of described STATCOM_max, obtain reactive currentEnhancing value I_max′：

I_max'＝I_max(1+Kf(t))；

Wherein, the gain multiple that K is control function;

Described PID output signal and described reactive current enhancing value I_max' stack, output STATCOMTransient state strengthens reactive current.

4. power system voltage stabilization control system as claimed in claim 3, is characterized in that, described steadyThe output reactive capability Q of the STATCOM that state control module obtains_SStatic synchronous as transient processThe reactive power reference qref Q of compensator_Sref, described reactive power reference qref Q_SrefIdle output with its actual measurementQ_SrealDifference after integration with controlled bus reference voltage V_refStack, acting in conjunction is in described static synchronousThe transient state of compensator strengthens to be controlled.