CN105406460A - Unit forced excitation and direct current emergency power support coordination control method based on wide-area measuring information - Google Patents

Abstract

The invention discloses a unit forced excitation and direct current emergency power support coordination control method based on wide-area measuring information, and relates to the field of safety and stability control of an electric power system. According to the method, the system real-time operation condition is generated based on the wide-area measuring information, the emergency control quantity required by instable contingency is calculated by employing the extended equal area criterion, the generator tripping and load shedding control costs are reduced by performing direct current emergency power support in advance, and the direct current short-line voltage is stabilized by employing synchronous unit forced excitation with high direct current power fluctuation sensitivity so that the direct current emergency power support control effect and system transient stabilization margin are improved.

Description

Unit based on wide area measurement information is encouraged by force and is supported control method for coordinating with direct-current emergency power

Technical field

The invention belongs to power system safety and stability control field, be specifically related to encourage by force based on the unit of wide area measurement information support control method for coordinating with direct-current emergency power.

Background technology

China region is wide, and primary energy distribution is very uneven with productivity dynamics, needs extensive long-distance sand transport, dissolves on a large scale, and determining China needs to adopt long-distance and large-capacity power transmission mode.In recent years, along with the enforcement that China's " transferring electricity from the west to the east " plans, interconnected network power transmission scale increases, power grid construction paces are accelerated, to the year two thousand twenty, China will build up the superhigh pressure AC and DC hybrid power system of trans-regional and long-distance transmissions great power rare in the world, and its complexity and difficulties run also is rare in the world.By to the end of the year in 2014, China is accumulative to be built up " three hand over four straight " UHV Transmission Engineering.According to national prevention and control of air pollution action plan embodiment, 4 times extra-high voltage direct-current transmission engineerings such as Xi Meng-Taizhou, Ning Dong-Shaoxing, upper Hai Miao-Linyi, North-south capital, Shanxi will be built up to the end of the year 2017, and 4 times ultra-high voltage AC transmission engineerings such as Huainan-Nanjing-Shanghai, Xi Meng-Shandong, Meng Xi-Tian Jinnan, elm horizontal stroke-Weifang.Along with the development of in large scale, complex structure, alternating current-direct current series-parallel connection bulk power grid that operational mode is changeable, there is great change in the operation characteristic of electrical network, is transitioned into the cooperation control of machine-net-direct current three by machine net cooperation control.

The structure of interconnected network system and operational mode become increasingly complex changeable, and its stability, once be destroyed, will cause huge economic loss and catastrophic consequence.Utilize the quick controllability of Large Copacity high voltage direct current, after electrical network suffers large disturbances, support by direct-current emergency power the acceleration energy reducing Critical Group unit effectively can improve the transient stability after interconnected network large disturbances, reduce unit shut algorithm and control cost.At present, direct-current emergency power is supported and is existingly furtherd investigate and obtain engineer applied improving in power system transient stability.But above-mentioned research solves two problems not yet:

1) do not consider that high-capacity direct current emergency DC power support causes alternating current circuit, direct current near region power flash-up, the circuit overload that then may cause or low along line drop, and then affect direct-current emergency power support effect.

2) direct-current emergency power is supported usually used as the single control measure after electrical network large disturbances at present, lacks the coordination controlled with traditional unit shut algorithm; And control measure depend on off-line strategy substantially, what high-power power flow transfer may be serious crosses control.

Document " generator based on WAMS encourages control program by force " (protecting electrical power system and control; in March, 2013; 41st volume, the 6th phase) propose to change system equivalent electromagnetic power by Critical Group DCgenerator motor field voltage after raising fault, thus influential system transient stability.This provides thinking for solving above-mentioned first kind problem.

WAMS provides new means to the monitoring of electric power system, analysis and control.The phasor measurement unit PMU of current practicality can gather multiclass operation of power networks state information in wide scope inter-sync, comprises busbar voltage phase place, generator built-in potential, merit angle etc. and can be delivered to data-centric with less time delay and complete synchronous process.And extended equal area criterion (EEAC) can carry out quantitative analysis assessment to system dynamic trajectory, detailed stability margin is provided, hives off and the information such as merit angle, accelerating power of equivalent one-of-a-kind system.This provides thinking for solving above-mentioned Equations of The Second Kind problem.

The patent No. is ZL200910026801.4, patent name is disclose a kind of transient rotor angle stability generator in " in transient safe and stable mode of power system method for identifying element participation factors " to hive off the recognition methods of generator participation factors in pattern.The method can be utilized by the present invention, the participation factors hived off in pattern by the transient rotor angle stability generator calculating each generator in acquisition Critical Group.

Summary of the invention

The object of the invention is: the wide area measurement information provided based on WAMS, encouraged by synchronous electric source strength, conventional unit shut algorithm and direct-current emergency power supports the cooperation control realizing source-net-direct current, and the preferential direct-current emergency power that plays is supported and reduced unit shut algorithm and control cost; Meanwhile, the larger synchronous unit of sensitivity that fluctuate with direct current power is utilized to encourage by force stable DC near region voltage, thus raising direct-current emergency power support control effects and power system transient stability nargin.

Specifically, the present invention adopts following technical scheme to realize, and comprises the following steps:

1) coefficient correlation of off-line Load flow calculation unit and direct current and the coefficient correlation of alternating current circuit and direct current, according to the system real time execution operating mode that wide area measurement information generates, perform step 2) ~ 6), described wide area measurement information comprises generator's power and angle, the real-time transmission power of circuit and direct current transmission power;

2) according to the direct current real-time running state information that DC control system provides, the direct current set D that can participate in emergency DC power support is determined;

3) each forecast failure is concentrated to carry out time-domain-simulation to forecast failure, extended equal area criterion is utilized to carry out quantitative analysis to simulation result, obtain generator to hive off and stability margin information, and be negative forecast failure F for wherein stability margin, perform step 3-1) ~ 3-3), described generator Clustering information comprises Critical Group information and remaining group's information:

3-1) calculate the emergency DC power support priority indicator of each direct current in direct current set D and power support party to;

3-2) according to the Emergency Assistance power maximum of each direct current in direct current set D under the coefficient correlation determination current working of alternating current circuit transmission power level and alternating current circuit and direct current, then power maximum Δ D is supported to the direct current set D direct-current emergency obtaining allowing of suing for peace _max;

Direct-current emergency 3-3) utilizing extended equal area criterion to calculate for forecast failure F supports target power Δ D, and revises the off-line unit shut algorithm strategy of this forecast failure;

4) after monitoring forecast failure F generation, perform revised off-line unit shut algorithm control measure, and make by L direct current execution emergency DC power support before the descending sequence of direct-current emergency power support priority indicator in direct current set D, wherein the numerical value of L is according to the Emergency Assistance power maximum summation of this L direct current system being not less than direct-current emergency support target power Δ D is that target is determined;

5) the generator Clustering information utilizing extended equal area criterion to calculate, from Critical Group unit, the relevant unit of direct current is extracted to the coefficient correlation of direct current according to unit, and send and encourage starting command by force, described direct current unit of being correlated with is the unit relevant to implementing emergency DC power support direct current;

6) according to the unit real-time power-angle and power information that WAMS provides, utilize the merit angle of the equivalent unit of extended equal area criterion computing system, when the merit angle of equivalent unit starts anti-wobble, send and encourage to the unit of being correlated with of the direct current in Critical Group by force and exit command, send encourage starting command by force to the unit of being correlated with of the direct current in remaining group.

Above-mentioned technical characteristic is further characterized in that, described step 1) in the method for off-line Load flow calculation unit and the coefficient correlation of direct current and the coefficient correlation of alternating current circuit and direct current as follows:

If the transmission power perturbation of i-th direct current is Δ P _dikeep i-th direct current both sides current conversion station ac bus voltage constant, by active power change and the change of unit reactive power of off-line Load flow calculation the whole network alternating current circuit, front N bar alternating current circuit is got according to the descending order of circuit active power change absolute value, get M platform unit according to the descending order of unit reactive power change absolute value, utilize formula (1) to calculate the coefficient correlation of each unit and i-th direct current and the coefficient correlation of each alternating current circuit and i-th direct current:

$\left\{\begin{array}{c}{r}_{L.j.i}=\frac{{\mathrm{\ΔP}}_{L.j}}{{\mathrm{\ΔP}}_{Di}}\\ r_{G.k.i}=\frac{{\mathrm{\ΔQ}}_{G.k}}{\underset{m=1}{\overset{M}{\Σ}}{\mathrm{\ΔQ}}_{G.m}}\end{array}\right.---\left(1\right)$

In formula, r _l.j.ifor the coefficient correlation of a jth alternating current circuit and i-th direct current, r _g.k.ifor the coefficient correlation of a kth unit and i-th direct current, wherein j=1,2 ..., N, k=1,2 ..., M; Δ P _l.jfor the active power of a jth alternating current circuit changes, Δ Q _g.kfor the reactive power of a kth unit changes, Δ Q _g.mit is the reactive power change of m unit.

Above-mentioned technical characteristic is further characterized in that, step 3-1) in direct current set D the direct-current emergency power of each direct current support priority indicator and power support party to defining method as follows:

1) utilize that the patent No. is ZL200910026801.4, patent name is that transient rotor angle stability generator in " in transient safe and stable mode of power system method for identifying element participation factors " hives off the recognition methods of generator participation factors in pattern, the participation factors that the transient rotor angle stability generator obtaining each generator in Critical Group hives off in pattern, utilizes formula (2) to calculate:

$\left\{\begin{array}{c}{X}_{in.i}^F=\underset{j=1}{\overset{S}{\Σ}}(p_j^F\·x_{in.i.j}^F)\\ X_{out.i}^F=\underset{j=1}{\overset{S}{\Σ}}(p_j^F\·x_{out.i.j}^F)\end{array}\right.---\left(2\right)$

In above-mentioned formula, be the Universal electric Distance geometry between the rectification side current conversion station of i-th direct current and Critical Group, be the Universal electric Distance geometry between the inverter side current conversion station of i-th direct current and Critical Group, for the participation factors that the transient rotor angle stability generator of the generator of jth in Critical Group hives off in pattern, for the electrical distance between the generator of jth in Critical Group and the rectification side current conversion station ac bus of i-th direct current, for the electrical distance between the generator of jth in Critical Group and the inverter side current conversion station ac bus of i-th direct current, S is generator number of units in Critical Group;

2) if then for forecast failure F, the power Emergency Assistance direction of i-th direct current is bring to power, direct-current emergency power is supported priority indicator and equaled otherwise the power Emergency Assistance direction of i-th direct current is back to fall power, direct-current emergency power is supported priority indicator and is equaled

Above-mentioned technical characteristic is further characterized in that, step 3-2) in direct current set D the computational methods of the Emergency Assistance power maximum of each direct current as follows:

First support priority indicator to each direct current sequence in direct current set D based on direct-current emergency power, utilize formula (3) to determine the Emergency Assistance power maximum of each direct current:

ΔD _max.i＝min(a _i·P _rate.i-P _act.i,ΔD _ACLim.i)(3)

Wherein, Δ D _max.ibe the Emergency Assistance power maximum of i-th direct current, a _ibe the urgent modulation multiple that i-th direct current allows, P _rate.ibe the rated capacity of i-th direct current, P _act.ibe the current transmission power of i-th direct current, Δ D _aCLim.ifor the Emergency Assistance power upper limit of i-th direct current by the restriction of N number of alternating current circuit ability to transmit electricity, if for the ability to transmit electricity room for promotion of a jth alternating current circuit, j=1,2 ..., N, then Δ D _aCLim.iminimum value according to the ability to transmit electricity room for promotion of N number of alternating current circuit is determined, wherein:

$P_{now.j}^{\′}=\left\{\begin{array}{c}{P}_{now.j}+\underset{I=1}{\overset{i-1}{\Σ}}({\mathrm{\ΔD}}_{max.I}\·r_{L.j.i}),i>1\\ P_{now.j},i=1\end{array}\right.$

P _max.jfor the total transfer capability of jth the alternating current circuit relevant to i-th direct current, P _now.jfor the transmission power of a jth alternating current circuit, P ' _now.jfor the transmission power of a revised jth alternating current circuit.

Above-mentioned technical characteristic is further characterized in that, step 3-3) specifically comprise the following steps:

Utilize the time-domain-simulation track of complementation group inertia central transformation to forecast failure F of extended equal area criterion to be polymerized, calculate corresponding equivalent one-of-a-kind system time become merit angle δ, mechanical output P _mwith electromagnetic power P _e, and perform following step: 3-3-1) utilize formula (4) to calculate and accelerate area A _inc:

$A_{inc}={\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_c}(P_m-P_e)d\mathrm{\δ}---\left(4\right)$

δ ₀and δ _cbe respectively fault and moment t occurs ₀with fault clearance moment t _cthe time change merit angle of equivalent one-of-a-kind system;

If 3-3-2) forecast failure F is without Off-line control strategy or Δ D _maxbe not less than Off-line control strategy and cut machine amount P _gwith cut lotus amount P _lsum, utilizes formula (5) to calculate direct-current emergency and support target power Δ D, and machine amount P is cut in order _gwith cut lotus amount P _lbe 0, otherwise perform 3-3-3):

$\mathrm{\Δ}D=\frac{A_{inc}-{\∫}_{{\mathrm{\δ}}_c}^{{\mathrm{\δ}}_{cr}}(P_e-P_m)d\mathrm{\δ}}{{\mathrm{\δ}}_{cr}-{\mathrm{\δ}}_e}---\left(5\right)$

Wherein, δ _efor emergency control performs moment t _ethe time change merit angle of corresponding equivalent one-of-a-kind system, δ _crfor the equivalent one-of-a-kind system merit angle critical value of setting, wherein t _e=t _c+ T _d, T _dfor emergency control performs time delay;

Direct-current emergency 3-3-3) is made to support target power Δ D=Δ D _max, and according to following different situations correction unit shut algorithm amount:

If Δ D _max>=P _l, lotus amount P is cut in order _lbe 0, cut machine amount P ' _g=P _g-Δ D+P _l; Otherwise lotus amount P ' is cut in order _l=P _l-Δ D, cuts machine amount P _gconstant.

Beneficial effect of the present invention is as follows: the present invention can realize that synchronous electric source strength is encouraged, traditional unit shut algorithm and direct-current emergency power support the emergency control scheme coordinated mutually, and based on the thought of " on-line pre-decision system; real-time matching ", after fault occurs, perform the direct-current emergency power worked out in advance for this fault support preferential emergency control measure.In head pendulum and the anti-wobble stage of power system transient stability, different units is taked to encourage by force, the control negative effect effectively avoiding unit to encourage by force may introducing.

Accompanying drawing explanation

Fig. 1 is the flow chart of the inventive method.

Embodiment

Referring to the flow chart shown in Fig. 1, the present invention is described in further detail.

In Fig. 1, step 1 is the coefficient correlation of off-line Load flow calculation unit and direct current and the coefficient correlation of alternating current circuit and direct current, has been calculated by off-line simulation.Specific implementation is: set the transmission power perturbation of i-th direct current as Δ P _dikeep i-th direct current both sides current conversion station ac bus voltage constant, by active power change and the change of unit reactive power of off-line Load flow calculation the whole network alternating current circuit, front N bar alternating current circuit is got according to the descending order of circuit active power change absolute value, get M platform unit according to the descending order of unit reactive power change absolute value, utilize formula (1) to calculate the coefficient correlation of each unit and i-th direct current and the coefficient correlation of each alternating current circuit and i-th direct current:

$\left\{\begin{array}{c}{r}_{L.j.i}=\frac{{\mathrm{\ΔP}}_{L.j}}{{\mathrm{\ΔP}}_{Di}}\\ r_{G.k.i}=\frac{{\mathrm{\ΔQ}}_{G.k}}{\underset{m=1}{\overset{M}{\Σ}}{\mathrm{\ΔQ}}_{G.m}}\end{array}\right.---\left(1\right)$

In formula, r _l.j.ifor the coefficient correlation of a jth alternating current circuit and i-th direct current, r _g.k.ifor the coefficient correlation of a kth unit and i-th direct current, wherein j=1,2 ..., N, k=1,2 ..., M; Δ P _l.jfor the active power of a jth alternating current circuit changes, Δ Q _g.kfor the reactive power of a kth unit changes, Δ Q _g.mit is the reactive power change of m unit.

In Fig. 1, step 2 ~ step 3 is the system real time execution operating modes generated according to wide area measurement information (comprising the information such as generator's power and angle, the real-time transmission power of circuit and direct current transmission power), the forecast failure that forecast failure is concentrated is emulated, and emergency control measure is worked out to unstability fault wherein.Specifically:

Step 2: according to direct current real-time running state information, determines the direct current set D that can participate in emergency DC power support.

Step 3: concentrate each forecast failure to carry out time-domain-simulation to forecast failure, extended equal area criterion (EEAC) is utilized to carry out quantitative analysis to simulation result, obtain generator to hive off the information such as (Critical Group, remaining group) and stability margin, for the forecast failure F that stability margin is negative, perform following calculating:

3-1) in set of computations D each direct-current emergency power support priority indicator and power support party to.

Circular: the participation factors that the transient rotor angle stability generator first obtaining each generator in Critical Group hives off in pattern, utilizes formula (2) to calculate:

$\left\{\begin{array}{c}{X}_{in.i}^F=\underset{j=1}{\overset{S}{\Σ}}(p_j^F\·x_{in.i.j}^F)\\ X_{out.i}^F=\underset{j=1}{\overset{S}{\Σ}}(p_j^F\·x_{out.i.j}^F)\end{array}\right.---\left(2\right)$

In above-mentioned formula, be the Universal electric Distance geometry between the rectification side current conversion station of i-th direct current and Critical Group, be the Universal electric Distance geometry between the inverter side current conversion station of i-th direct current and Critical Group, for the participation factors that the transient rotor angle stability generator of the generator of jth in Critical Group hives off in pattern, for the electrical distance between the generator of jth in Critical Group and the rectification side current conversion station ac bus of i-th direct current, for the electrical distance between the generator of jth in Critical Group and the inverter side current conversion station ac bus of i-th direct current, S is generator number of units in Critical Group;

If then for forecast failure F, the power Emergency Assistance direction of i-th direct current is bring to power, direct-current emergency power is supported priority indicator and equaled otherwise the power Emergency Assistance direction of i-th direct current is back to fall power, direct-current emergency power is supported priority indicator and is equaled

Wherein, in above-mentioned acquisition Critical Group, the hive off method of the participation factors in pattern of the transient rotor angle stability generator of each generator be the patent No. is ZL200910026801.4, patent name to hive off the recognition methods of generator participation factors in pattern for the transient rotor angle stability generator in " in transient safe and stable mode of power system method for identifying element participation factors ", specifically see its specification embodiment the 0017th section, i.e. " the identification of generator participation factors in pattern that transient rotor angle stability generator is hived off, if transient rotor angle stability nargin is less than 0, for Critical Group generator, calculate disturbed track acceleration kinetic energy of each generator in Critical Group when dynamic saddle point (DSP), in Critical Group, generator accelerates the maximum of kinetic energy as benchmark, using the participation factors of the ratio of the acceleration kinetic energy of each generator in Critical Group and this fiducial value as each generator, for remainder mass-sending motor, calculate the deceleration kinetic energy of disturbed track each generator in the remaining group of DSP, equally accelerate the maximum of kinetic energy as benchmark using generator in Critical Group, using the participation factors of the opposite number of the ratio of the deceleration kinetic energy of each generator in remaining group and this fiducial value as each generator, if transient rotor angle stability nargin is more than or equal to 0, for Critical Group generator, when first will determine that the acceleration kinetic energy of the pendulum time equivalent generator of middle Critical Group that disturbed track provides in stable mode reaches maximum, in this moment Critical Group, generator accelerates the maximum of kinetic energy as benchmark, using the participation factors of the ratio of the acceleration kinetic energy in each this moment of generator in Critical Group and this fiducial value as each generator, for remainder mass-sending motor, accelerate the maximum of kinetic energy as benchmark using generator in this moment Critical Group equally, using the participation factors of the opposite number of the ratio of the deceleration kinetic energy in each this moment of generator in remaining group and this fiducial value as each generator ".

3-2) according to alternating current circuit transmission power, alternating current circuit and direct current coefficient correlation, first priority indicator is supported to each direct current sequence in direct current set D based on direct-current emergency power, utilize the Emergency Assistance power maximum of each direct current in direct current set D under formula (3) current working, then power maximum Δ D is supported to the set D direct-current emergency obtaining allowing of suing for peace _max.

ΔD _max.i＝min(a _i·P _rate.i-P _act.i,ΔD _ACLim.i)(3)

Wherein, Δ D _max.ibe the Emergency Assistance power maximum of i-th direct current, a _ibe the urgent modulation multiple (usual value 1.1 ~ 1.3) that i-th direct current allows, P _rate.ibe the rated capacity of i-th direct current, P _act.ibe the current transmission power of i-th direct current, Δ D _aCLim.ifor the Emergency Assistance power upper limit of i-th direct current by the restriction of N number of alternating current circuit ability to transmit electricity, if for the ability to transmit electricity room for promotion of a jth alternating current circuit, j=1,2 ..., N, then Δ D _aCLim.iminimum value according to the ability to transmit electricity room for promotion of N number of alternating current circuit is determined, wherein:

$P_{now.j}^{\′}=\left\{\begin{array}{c}{P}_{now.j}+\underset{I=1}{\overset{i-1}{\Σ}}({\mathrm{\ΔD}}_{max.I}\·r_{L.j.i}),i>1\\ P_{now.j},i=1\end{array}\right.$

P _max.jfor the total transfer capability of jth the alternating current circuit relevant to i-th direct current, P _now.jfor the transmission power of a jth alternating current circuit, P ' _now.jfor the transmission power of a revised jth alternating current circuit.

Direct-current emergency 3-3) utilizing extended equal area criterion to calculate for forecast failure F supports target power Δ D, and the off-line unit shut algorithm strategy of this forecast failure is revised, comprise the following steps: utilize the time-domain-simulation track of complementation group inertia central transformation (CCCOI-RM) to forecast failure of EEAC method to be polymerized, obtain corresponding equivalent one-of-a-kind system time become merit angle δ, mechanical output P _mwith electromagnetic power P _e, the direct-current emergency calculated for forecast failure F is supported target power Δ D, and is revised the off-line unit shut algorithm strategy of this forecast failure.Circular is as follows:

First utilize formula (4) to calculate and accelerate area A _inc:

$A_{inc}={\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_c}(P_m-P_e)d\mathrm{\δ}---\left(4\right)$

δ ₀and δ _cbe respectively fault and moment t occurs ₀with fault clearance moment t _cthe time change merit angle of equivalent one-of-a-kind system.

If this fault is without Off-line control strategy or Δ D _maxbe not less than Off-line control strategy and cut machine amount P _gwith cut lotus amount P _lsum, utilizes formula (5) to calculate direct-current emergency and support target power Δ D, and machine amount P is cut in order _gwith cut lotus amount P _lbe 0.

$\mathrm{\Δ}D=\frac{A_{inc}-{\∫}_{{\mathrm{\δ}}_c}^{{\mathrm{\δ}}_{cr}}(P_e-P_m)d\mathrm{\δ}}{{\mathrm{\δ}}_{cr}-{\mathrm{\δ}}_e}---\left(5\right)$

Wherein, δ _efor emergency control performs moment t _ethe time change merit angle of corresponding equivalent one-of-a-kind system, δ _crfor the equivalent one-of-a-kind system merit angle critical value of setting, wherein t _e=t _c+ T _d, T _dfor emergency control performs time delay, general value is 200ms.

Otherwise, make direct-current emergency support target power Δ D=Δ D _max, and according to following different situations correction unit shut algorithm amount: if Δ D _max>=P _l, lotus amount P is cut in order _lbe 0, cut machine amount P ' _g=P _g-Δ D+P _l; Otherwise lotus amount P ' is cut in order _l=P _l-Δ D, cuts machine amount P _gconstant.

Step 4 ~ 6 implement emergency control measure after monitoring forecast failure F generation and unit encourages measure by force, specific as follows:

Step 4: after monitoring forecast failure F generation, perform revised off-line unit shut algorithm control measure, and make by L direct current execution emergency DC power support before the descending sequence of direct-current emergency power support priority indicator in direct current set D, wherein the numerical value of L is according to the Emergency Assistance power maximum summation of this L direct current system being not less than direct-current emergency support target power Δ D is that target is determined.

Step 5: according to the coefficient correlation of unit and direct current, and the unit Clustering information utilizing EEAC to calculate, extract from Critical Group unit and the relevant unit implementing emergency DC power support direct current (calling " direct current be correlated with unit " in the following text), transmission encourages starting command by force.

Step 6: the unit real-time power-angle and power information provided according to WAMS, utilize the merit angle of the equivalent unit of EEAC computing system, when the merit angle of equivalent unit starts anti-wobble, send and encourage to the unit of being correlated with of the direct current in Critical Group by force and exit command, send encourage starting command by force to the unit of being correlated with of the direct current in remaining group.

Although the present invention with preferred embodiment openly as above, embodiment is not of the present invention for limiting.Without departing from the spirit and scope of the invention, any equivalence change done or retouching, belong to the protection range of the present invention equally.Therefore the content that protection scope of the present invention should define with the claim of the application is standard.

Claims (5)

1. encourage by force based on the unit of wide area measurement information and support control method for coordinating with direct-current emergency power, it is characterized in that, comprise the steps:

1) coefficient correlation of off-line Load flow calculation unit and direct current and the coefficient correlation of alternating current circuit and direct current, according to the system real time execution operating mode that wide area measurement information generates, perform step 2) ~ 6), described wide area measurement information comprises generator's power and angle, the real-time transmission power of circuit and direct current transmission power;

2) according to the direct current real-time running state information that DC control system provides, the direct current set D that can participate in emergency DC power support is determined;

3) each forecast failure is concentrated to carry out time-domain-simulation to forecast failure, extended equal area criterion is utilized to carry out quantitative analysis to simulation result, obtain generator to hive off and stability margin information, and be negative forecast failure F for wherein stability margin, perform step 3-1) ~ 3-3), described generator Clustering information comprises Critical Group information and remaining group's information:

3-1) calculate the emergency DC power support priority indicator of each direct current in direct current set D and power support party to;

3-2) according to the Emergency Assistance power maximum of each direct current in direct current set D under the coefficient correlation determination current working of alternating current circuit transmission power level and alternating current circuit and direct current, then power maximum Δ D is supported to the direct current set D direct-current emergency obtaining allowing of suing for peace _max;

Direct-current emergency 3-3) utilizing extended equal area criterion to calculate for forecast failure F supports target power Δ D, and revises the off-line unit shut algorithm strategy of this forecast failure;

4) after monitoring forecast failure F generation, perform revised off-line unit shut algorithm control measure, and make by L direct current execution emergency DC power support before the descending sequence of direct-current emergency power support priority indicator in direct current set D, wherein the numerical value of L is according to the Emergency Assistance power maximum summation of this L direct current system being not less than direct-current emergency support target power Δ D is that target is determined;

5) the generator Clustering information utilizing extended equal area criterion to calculate, from Critical Group unit, the relevant unit of direct current is extracted to the coefficient correlation of direct current according to unit, and send and encourage starting command by force, described direct current unit of being correlated with is the unit relevant to implementing emergency DC power support direct current;

6) according to the unit real-time power-angle and power information that WAMS provides, utilize the merit angle of the equivalent unit of extended equal area criterion computing system, when the merit angle of equivalent unit starts anti-wobble, send and encourage to the unit of being correlated with of the direct current in Critical Group by force and exit command, send encourage starting command by force to the unit of being correlated with of the direct current in remaining group.

2. the unit based on wide area measurement information according to claim 1 is encouraged by force and is supported control method for coordinating with direct-current emergency power, it is characterized in that, described step 1) in the method for off-line Load flow calculation unit and the coefficient correlation of direct current and the coefficient correlation of alternating current circuit and direct current as follows:

If the transmission power perturbation of i-th direct current is Δ P _dikeep i-th direct current both sides current conversion station ac bus voltage constant, by active power change and the change of unit reactive power of off-line Load flow calculation the whole network alternating current circuit, front N bar alternating current circuit is got according to the descending order of circuit active power change absolute value, get M platform unit according to the descending order of unit reactive power change absolute value, utilize formula (1) to calculate the coefficient correlation of each unit and i-th direct current and the coefficient correlation of each alternating current circuit and i-th direct current:

$\left\{\begin{array}{c}{r}_{L.j.i}=\frac{{\mathrm{\ΔP}}_{L.j}}{{\mathrm{\ΔP}}_{Di}}\\ r_{G.k.i}=\frac{{\mathrm{\ΔQ}}_{G.k}}{\underset{m=1}{\overset{M}{\Σ}}{\mathrm{\ΔQ}}_{G.m}}\end{array}\right.---\left(1\right)$

In formula, r _l.j.ifor the coefficient correlation of a jth alternating current circuit and i-th direct current, r _g.k.ifor the coefficient correlation of a kth unit and i-th direct current, wherein j=1,2 ..., N, k=1,2 ..., M; Δ P _l.jfor the active power of a jth alternating current circuit changes, Δ Q _g.kfor the reactive power of a kth unit changes, Δ Q _g.mit is the reactive power change of m unit.

3. the unit based on wide area measurement information according to claim 1 is encouraged by force and is supported control method for coordinating with direct-current emergency power, it is characterized in that, step 3-1) in direct current set D the direct-current emergency power of each direct current support priority indicator and power support party to defining method as follows:

1) utilize that the patent No. is ZL200910026801.4, patent name is that transient rotor angle stability generator in " in transient safe and stable mode of power system method for identifying element participation factors " hives off the recognition methods of generator participation factors in pattern, the participation factors that the transient rotor angle stability generator obtaining each generator in Critical Group hives off in pattern, utilizes formula (2) to calculate:

$\left\{\begin{array}{c}{X}_{in.i}^F=\underset{j=1}{\overset{S}{\Σ}}(p_j^F\·x_{in.i.j}^F)\\ X_{out.i}^F=\underset{j=1}{\overset{S}{\Σ}}\left(p_j^F\·x_{out.i.j}^F\right)\end{array}\right.---\left(2\right)$

In above-mentioned formula, be the Universal electric Distance geometry between the rectification side current conversion station of i-th direct current and Critical Group, be the Universal electric Distance geometry between the inverter side current conversion station of i-th direct current and Critical Group, for the participation factors that the transient rotor angle stability generator of the generator of jth in Critical Group hives off in pattern, for the electrical distance between the generator of jth in Critical Group and the rectification side current conversion station ac bus of i-th direct current, for the electrical distance between the generator of jth in Critical Group and the inverter side current conversion station ac bus of i-th direct current, S is generator number of units in Critical Group;

2) if then for forecast failure F, the power Emergency Assistance direction of i-th direct current is bring to power, direct-current emergency power is supported priority indicator and equaled otherwise the power Emergency Assistance direction of i-th direct current is back to fall power, direct-current emergency power is supported priority indicator and is equaled

4. the unit based on wide area measurement information according to claim 1 is encouraged by force and is supported control method for coordinating with direct-current emergency power, it is characterized in that, step 3-2) in direct current set D the computational methods of the Emergency Assistance power maximum of each direct current as follows:

First support priority indicator to each direct current sequence in direct current set D based on direct-current emergency power, utilize formula (3) to determine the Emergency Assistance power maximum of each direct current:

ΔD _max.i＝min(a _i·P _rate.i-P _act.i,ΔD _ACLim.i)(3)

Wherein, Δ D _max.ibe the Emergency Assistance power maximum of i-th direct current, a _ibe the urgent modulation multiple that i-th direct current allows, P _rate.ibe the rated capacity of i-th direct current, P _act.ibe the current transmission power of i-th direct current, Δ D _aCLim.ifor the Emergency Assistance power upper limit of i-th direct current by the restriction of N number of alternating current circuit ability to transmit electricity, if for the ability to transmit electricity room for promotion of a jth alternating current circuit, j=1,2 ..., N, then Δ D _aCLim.iminimum value according to the ability to transmit electricity room for promotion of N number of alternating current circuit is determined, wherein:

$P_{now.j}^{\′}=\left\{\begin{array}{c}{P}_{now.j}+\underset{I=1}{\overset{i-1}{\Σ}}({\mathrm{\ΔD}}_{max.I}\·r_{L.j.i}),i>1\\ P_{now.j},i=1\end{array}\right.$

P _max.jfor the total transfer capability of jth the alternating current circuit relevant to i-th direct current, P _now.jfor the transmission power of a jth alternating current circuit, P ' _now.jfor the transmission power of a revised jth alternating current circuit.

5. the unit based on wide area measurement information according to claim 1 is encouraged by force and is supported control method for coordinating with direct-current emergency power, it is characterized in that, step 3-3) specifically comprise the following steps:

Utilize the time-domain-simulation track of complementation group inertia central transformation to forecast failure F of extended equal area criterion to be polymerized, calculate corresponding equivalent one-of-a-kind system time become merit angle δ, mechanical output Pm and electromagnetic power Pe, and perform following step:

3-3-1) utilize formula (4) to calculate and accelerate area A inc:

$A_{inc}={\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_c}(P_m-P_e)d\mathrm{\δ}---\left(4\right)$

δ 0 and δ c is respectively the time change merit angle that the equivalent one-of-a-kind system of moment t0 and fault clearance moment tc occurs fault;

If 3-3-2) forecast failure F is not less than Off-line control strategy without Off-line control strategy or Δ Dmax and cuts machine amount P _gwith cut lotus amount P _lsum, utilizes formula (5) to calculate direct-current emergency and support target power Δ D, and machine amount P is cut in order _gwith cut lotus amount P _lbe 0, otherwise perform 3-3-3):

$\mathrm{\Δ}D=\frac{A_{inc}-{\∫}_{{\mathrm{\δ}}_c}^{{\mathrm{\δ}}_{cr}}(P_e-P_m)d\mathrm{\δ}}{{\mathrm{\δ}}_{cr}-{\mathrm{\δ}}_e}---\left(5\right)$

Wherein, δ e is the time change merit angle that emergency control performs the corresponding equivalent one-of-a-kind system of moment te, and δ cr is the equivalent one-of-a-kind system merit angle critical value of setting, and wherein te=tc+Td, Td are that emergency control performs time delay;

Direct-current emergency 3-3-3) is made to support target power Δ D=Δ Dmax, and according to following different situations correction unit shut algorithm amount:

If Δ Dmax>=P _l, lotus amount P is cut in order _lbe 0, cut machine amount P ' _g=P _g-Δ D+P _l; Otherwise lotus amount P ' is cut in order _l=P _l-Δ D, cuts machine amount P _gconstant.