CN102709918A - Reactive power control method of grid gateway based on automatic volume control (AVC) system - Google Patents

Abstract

The invention provides a reactive power control method of a grid gateway based on an automatic volume control (AVC) system. The reactive power control method comprises the following steps: obtaining the relation curve between the general active power delivered from an upstream gateway and the corresponding average coordinating power factor limit value according to the load flow calculation data and the restriction condition of a grid; monitoring the reactive power delivered from the pressure side in every transformer in an upper main network in real time, calculating the limit value of the upstream gateway coordinated power factor of every transformer substation according to the relation curve; calculating the limit value of the coordinated power factor of a downstream gateway according to the limit value of the upstream gateway coordinated power factor; updating a control parameter of the AVC system according to the limit value of the power factor of the grid downstream gateway, and regulating the reactive power of the grid gateway according to the control parameter. According to the technology provided in the invention, the safety running of the upper main network is fully considered, the reactive regulating ability and the active load level of a lower branch network are also considered; therefore the mismatch problem possibly caused by the reactive/voltage regulation of the upper and lower grids is solved, and the voltage quality of the grid is further improved.

Description

Electrical network critical point Reactive Power Control method based on the AVC system

Technical field

The present invention relates to the Reactive Power Control method, particularly relate to a kind of electrical network critical point Reactive Power Control method based on the AVC system.

Background technology

Current; It has been a kind of important technical that solves the REACTIVE POWER regulation and control that voltage is controlled (AVC) system automatically, readjusts through what electric network reactive-load was distributed, guarantees that operation of power networks is at safer, a more economical state; And in the AVC implementation procedure, the whole network idle work optimization is core and basis.

General technology based on AVC system realization idle work optimization, in actual motion, the formulation of AVC Control Parameter is according to relevant guide rule regulation and relies on expertise directly to issue; Although this actual operating state that reacts electrical network to a certain extent; Yet, along with the fast development of electrical network, and the inherent limitation of expertise subjectivity; The mode that directly issues according to history data and expertise; Lagged behind the state of development of electrical network, can't quantitatively weigh the idle ability to bear of being held electrical network, and its setting range deviation is bigger; Cause to idle coordination control weak effect between electrical network the development trend that can not incompatible big electrical network and the fast development of load level far away.

Summary of the invention

Based on this; Be necessary quantitatively to weigh the idle ability to bear of being held electrical network to above-mentioned prior art; And its setting range deviation is bigger, causes the problem to idle coordination control weak effect between electrical network, and a kind of electrical network critical point Reactive Power Control method based on the AVC system is provided.

A kind of electrical network critical point Reactive Power Control method based on the AVC system comprises the steps:

According to the trend calculated data constraints of electrical network, obtain the relation curve between total active power of sending under the critical point, the upper reaches and the corresponding average coordinating power factor limit value;

Monitor the active power of sending under each the transformer medium voltage side in the major network of upper strata in real time, and calculate critical point, the upper reaches coordinating power factor limit value of each transformer station according to said relation curve;

Calculate the coordinating power factor limit value at critical point, downstream according to critical point, said upper reaches coordinating power factor limit value;

Upgrade the Control Parameter of AVC system according to the power factor limit value at critical point, said electrical network downstream, and according to the reactive power at said Control Parameter regulation and control electrical network critical point.

Above-mentioned electrical network critical point Reactive Power Control method based on the AVC system is through formulating the relation curve of the active power sent under the critical point, the upper reaches and average coordinating power factor limit value, with the quantitative idle ability to bear of being held electrical network of having weighed; Taken into full account the safe operation of upper strata major network; To the coordinating power factor limit value at each transformer station each critical point, transformer station upper reaches of burden with power level error alienation of upper strata major network,, taking into account under the idle ability of regulation and control and the horizontal prerequisite of burden with power that lower floor's subnet possessed so that realize reactive power layering and zoning in-situ balancing; Calculate the coordinating power factor limit value at critical point, downstream; The coordinating power factor limit value at the critical point, downstream that obtains according to adjusting carries out idle regulation and control as AVC critical point power factor controlling parameter, facilitates the coordination control of higher level's electrical network and subordinate's electric network reactive-load/regulating and controlling voltage; Solved the mismatch problems that electric network reactive-load/regulating and controlling voltage possibly occur; Further improve the quality of voltage of electrical network, reduce via net loss, alleviated the reactive balance pressure of upper strata major network; Thereby guaranteed the safe operation of major network, improved the safety and stability economical operation of electrical network.

Description of drawings

Fig. 1 is the electrical network critical point Reactive Power Control method flow diagram based on the AVC system of an embodiment;

Fig. 2 is the active power of an embodiment and the relation curve coordinate diagram of average coordinating power factor limit value;

Fig. 3 to Fig. 5 is the trend contrast situation sketch map of practical operation situation (X1), the inventive method (X2), existing idle control technique (X3).

Embodiment

Below in conjunction with accompanying drawing the embodiment of the electrical network critical point Reactive Power Control method based on the AVC system of the present invention is described in detail.

Fig. 1 illustrates the electrical network critical point Reactive Power Control method flow diagram based on the AVC system of the embodiment that knows clearly, mainly comprises the steps:

Step S1 according to the trend calculated data constraints of electrical network, obtains the relation curve between total active power of sending under the critical point, the upper reaches and the corresponding average coordinating power factor limit value.

Particularly, the trend calculated data comprises: a circuit-switched data, transformer parameter, various operational mode loads and generator output data.

Particularly, constraints comprises: control variables constraints and state variable constraints; Wherein, control variables constraints comprises that generator reactive goes out the force vector bound, the maximum reactive power compensation vector of transformer bound, transformer tapping gear vector bound; State variable constraints comprises busbar voltage amplitude vector bound, and virtual power supply is not arranged the idle force vector bound that goes out.

In one embodiment, the step of obtaining the relation curve between the active power sent under the critical point, the upper reaches and the corresponding average coordinating power factor limit value specifically comprises:

Step S101 sets up first Mathematical Modeling of the average coordinating power factor limit value at critical point, the upper reaches; Wherein, this Mathematical Modeling is used for calculating the average coordinating power factor limit value at the critical point, the upper reaches of satisfying said constraints according to the load level under the operational mode of setting.

Particularly, said first Mathematical Modeling comprises formula:

min?f(Q _1G，T _1K，Q _1C)＝F _min.0 (1)

s.t.h(Q _1G，T _1K，Q _1C)＝0 (2)

$\left\{\begin{array}{c}{Q}_{1\mathrm{GL}}\≤Q_{1G}\≤Q_{1\mathrm{GH}}\\ T_{1\mathrm{KL}}\≤T_{1K}\≤T_{1\mathrm{KH}}\\ Q_{1\mathrm{CL}}\≤Q_{1C}\≤Q_{1\mathrm{CH}}\\ V_{1\mathrm{BL}}\≤V_{1B}\≤V_{1\mathrm{BH}}\\ Q_{1\mathrm{ZL}}\≤Q_{1Z}\≤Q_{1\mathrm{ZH}}\end{array}\right.---\left(3\right)$

In the formula, F _Min.0Be target function, Q _1G, T _1K, Q _1CBe the control variables of upper strata major network transformer station, wherein Q _1GExpression generator idle goes out force vector, T _1KRepresent each transformer tapping gear vector, Q _1CReactive power compensation vector for each transformer; V _1BAnd Q _1ZBe state variable, V wherein _1BThe voltage magnitude vector of each bus of expression upper strata major network transformer station, Q _1ZFor virtual power supply is not arranged the idle force vector that goes out; Subscript L and H represent the lower limit and the higher limit of relevant variable respectively.

Set up corresponding Mathematical Modeling according to the load level under the typical operation modes; In the restriction range of control variables, seek the average coordinating power factor limit value at critical point, the upper reaches, for example; In big operational mode of summer; Obtain critical point lagging power-factor lower limit,, obtain critical point leading power factor lower limit in little operational mode of winter.

Step S102, according to first Mathematical Modeling, when calculating the downward straton net conveying of upper strata major network different active power, the average power factor limit value at critical point, the corresponding upper reaches, as an embodiment, computational process specifically comprises the steps:

A, according to trend calculated data constraints, calculate the downward straton net of upper strata major network and carry the total power value of active power; The active power of each transformer medium voltage side adds up in the upper strata major network that is about to monitor, and obtains the downward straton net of upper strata major network and carries meritorious total power value P _Always

B, the generating set that capacity in the major network of upper strata is maximum are made as the balance node of the whole network, and the transformer station that chooses the HVDC drop point is as not arranging the idle website of exerting oneself.

C, preset all transformer medium voltage side power factors are identical initial value, and this initial value are made as the initial value of the average coordinating power factor limit value at critical point, the upper reaches; For example, making the transformer medium voltage side power factor initial value of the whole network upper strata major network is 1.0, and it is made as the initial value storage of the average coordinating power factor limit value at critical point, the upper reaches.

Initial value and each transformer station's medium voltage side active power of d, the average coordinating power factor limit value of basis, the reactive power of modification transformer medium voltage side is carried out trend then and is calculated.

E, according to the constraints in the said Mathematical Modeling, judge said trend result calculated, obtain the upper strata major network under different operational modes, the average coordinating power factor limit value that total power value is corresponding.

Particularly, after trend was calculated end, whether inspection control variables and state variable be out-of-limit; The power plant is idle exerts oneself when out-of-limit when occurring, and out-of-limit power plant is revised as the PQ node by the PV node, and idle exerting oneself is set to the border of out-of-limit value; If the not arrangement out-of-limit or virtual reactive power source of substation bus bar voltage is idle exert oneself out-of-limit; Then revise near the magnitude of voltage of the generating brand-name computer end of out-of-limit bus, and coordinate near the switching of the capacitor/reactor of the transformer station of out-of-limit node, to revise the relevant parameter that trend is calculated; Recomputate trend then; The power plant is idle exerts oneself not out-of-limitly up to satisfying simultaneously, and substation bus bar voltage is qualified, and virtual reactive power source is not arranged idle these three conditions in allowed band of exerting oneself; Show that power factor meets the requirement of upper strata major network safe operation, then upgrade and store this power factor; Get into the cycle calculations flow process then, make power factor value deduct 0.001, big operational mode of summer is a lagging power-factor; Little operational mode of winter is a leading power factor, and repeating step a～d can't satisfy above-mentioned condition simultaneously up to various calculation of tidal current; Then read the power factor of storage; Can obtain under this operational mode, major network downward straton in upper strata is off the net, and to send active power be P when total, the average coordinating power factor limit value at critical point, the upper reaches.

Step S103 simulates the relation curve between the average coordinating power factor limit value at total active power that major network downward straton net in upper strata carries and corresponding critical point, the upper reaches according to said average power factor limit value; Particularly, under the operational mode of choosing, choose the tangible a plurality of load level P of discrimination _Always, calculate the average power factor limit value at critical point, the corresponding upper reaches, through coordinate system with above-mentioned P _AlwaysCorresponding discrete point carries out match with the curve of smooth and continuous, works up under this operational mode, the relation curve of the average coordinating power factor limit value at the upper reaches critical point relevant with load.

The above-mentioned relation curve can quantitatively be weighed the upper strata major network to sending active power P under lower floor's subnet _AlwaysThe time; The upper strata major network is to the idle maximum bearing ability of lower floor's subnet; Avoid lower floor's subnet to cause between the superior and the subordinate's electrical network the unreasonable of reactive power to flow, guarantee that the reactive voltage regulation and control level of electrical network is unaffected as a balance node upper strata major network; Eliminate system safety hidden danger, prevented the generation of voltage collapse accident.

Step S2 monitors the active power of sending under each the transformer medium voltage side in the major network of upper strata in real time, and according to said relation curve and critical point, upper reaches coordinating power factor limit value, calculates critical point, the upper reaches coordinating power factor limit value of each transformer station; Promptly through monitoring the active power of sending under each transformer station's medium voltage side; Calculate the active power of sending under each transformer station's medium voltage side, and, obtain the average coordinating power factor limit value at the upper reaches critical point corresponding according to said relation curve with this total active power with its total active power of acquisition that adds up; Adopt linearization process; The coordinating power factor limit value at each critical point, transformer station upper reaches of differentiation as an embodiment, comprises the steps:

Step S201; Monitor the active power of sending under each transformer medium voltage side in the major network of upper strata respectively; Calculate the active power of sending under each transformer station's medium voltage side; And, obtain the average coordinating power factor limit value at the upper reaches critical point corresponding according to said relation curve with this total active power with its total active power of acquisition that adds up; Particularly, monitor the active power of sending under each transformer medium voltage side, calculate the active power P that send under each transformer station's medium voltage side, it is added up obtains total active power P _Always, according to the above-mentioned relation curve, the limit value cos θ of the average coordinating power factor at the critical point, the upper reaches that obtains loading relevant _l

For example, under big operational mode of summer, be not less than 0.95 rigid requirement in order to satisfy " power system voltage and the technological guide rule of var " for transformer critical point power factor, then its definite value is:

$\cos {\mathrm{\θ}}_l=\left\{\begin{array}{cc}\cos {\mathrm{\θ}}_l& \cos {\mathrm{\θ}}_l>0.95\\ 0.95& \cos {\mathrm{\θ}}_l\≤0.95\end{array}\right.---\left(4\right)$

Under little operational mode of winter, then its definite value is:

cosθ _l＝cosθ _l (5)

Step S202 according to the active power of sending under each transformer medium voltage side in the upper strata major network of said monitoring, calculates the active power P that send under each transformer station's medium voltage side, obtains the average active power P that send under transformer station's medium voltage side in the major network of upper strata _AvWith the maximum active power P that send down _Max

Step S203 carries out linearization process according to said average active power and maximum active power to the active power of sending under said each transformer station's medium voltage side, obtains corresponding critical point, the upper reaches coordinating power factor limit value of each transformer station in the major network of upper strata;

Wherein, the process of said linearization process comprises formula:

$\cos \mathrm{\θ}=\left\{\begin{array}{cc}\frac{P-P_{\mathrm{av}}}{P_{\max }-P_{\mathrm{av}}}(\cos {\mathrm{\θ}}_h-\cos {\mathrm{\θ}}_l)+{\cos \mathrm{\θ}}_l& P>P_{\mathrm{av}}\\ \cos {\mathrm{\θ}}_l& P\≤P_{\mathrm{av}}\end{array}\right.---\left(6\right)$

In the formula, P is the active power of sending under transformer station's medium voltage side, cos θ _lBe the average coordinating power factor limit value at critical point, the upper reaches, P _AvBe the average active power of each transformer station's medium voltage side, P _MaxBe the maximum active power of sending under transformer station's medium voltage side, cos θ _hBe the lowest power factor that the heaviest substation's permission of medium voltage side load is sent down, cos θ is the coordinating power factor limit value at critical point, the upper reaches.

Step S3 calculates the coordinating power factor limit value at critical point, downstream according to critical point, said upper reaches coordinating power factor limit value; In one embodiment, the process of the coordinating power factor limit value at calculating critical point, downstream comprises the steps:

Step S301 sets up second Mathematical Modeling of the average coordinating power factor limit value at critical point, downstream; Wherein, this Mathematical Modeling is used for calculating the average coordinating power factor limit value at the critical point, downstream of satisfying said constraints according to the load level under the operational mode of setting; Particularly, second Mathematical Modeling comprises formula:

min?f(Q _2G，T _2K，Q _2C)＝f _lim.0 (8)

s.t.h(Q _2G，T _2K，Q _2C)＝0 (9)

$\left\{\begin{array}{c}{Q}_{2\mathrm{GL}}\≤Q_{2G}\≤Q_{2\mathrm{GH}}\\ T_{2\mathrm{KL}}\≤T_{2K}\≤T_{2\mathrm{KH}}\\ Q_{2\mathrm{CL}}\≤Q_{2C}\≤Q_{2\mathrm{CH}}\\ V_{2\mathrm{BL}}\≤V_{2B}\≤V_{2\mathrm{BH}}\\ \cos {\mathrm{\θ}}_0\≥\cos \mathrm{\θ}\end{array}\right.---\left(10\right)$

In the formula, f _Lim.0Be target function, Q _2G, T _2KAnd Q _2CBe the control variables of subnet transformer station of lower floor, wherein Q _2GThe expression generator reactive goes out force vector, T _2KRepresent each transformer tapping gear vector, Q _2CBe the reactive power compensation vector of each transformer, V _2BWith cos θ be state variable, V wherein _2BThe voltage magnitude vector of expression lower floor subnet substation bus bar, cos θ is the coordinating power factor limit value at critical point, the upper reaches, cos θ ₀Be the power factor at real-time critical point, the upper reaches of monitoring, subscript L and H represent the lower limit and the higher limit of relevant variable respectively.

Step S302, under the operational mode of setting, according to the trend section that send maximum active power and minimum active power under transformer station's medium voltage side, the active power of sending under each transformer medium voltage side in the major network of monitoring upper strata.

Step S303 according to the relation curve between total active power of sending under the critical point, the upper reaches and the corresponding average coordinating power factor limit value with according to said linearization process process, obtains respectively and send maximum active power P under transformer station's medium voltage side _HWith minimum active power P _LThe power factor limit value cos θ at corresponding critical point, the upper reaches _HWith cos θ _L

Step S304 according to second Mathematical Modeling, calculates under the said transformer station medium voltage side and send maximum active power P _HWith minimum active power P _LThe coordinating power factor limit value at corresponding critical point, downstream; Particularly, according to the target function f of second Mathematical Modeling _Lim.0, carry out optimizing and calculate, calculate the meritorious P that is respectively _HAnd P _L, satisfying under the coordinating power factor limit value constraints of critical point, the upper reaches, corresponding critical point, downstream coordinating power factor limit value is respectively

With

Step S305; According to the coordinating power factor limit value that send the corresponding critical point, the upper reaches of maximum active power and minimum active power under the said transformer station medium voltage side; And the coordinating power factor limit value that send the critical point, downstream of maximum active power and minimum active power correspondence under the said transformer station medium voltage side; Calculate when sending active power P under transformer station's medium voltage side the coordinating power factor limit value at critical point, downstream; Wherein, the process of the coordinating power factor limit value at calculating critical point, downstream comprises formula:

In the formula;

is the coordinating power factor limit value at critical point, downstream; Cos θ is when sending active power P under transformer station's medium voltage side, the coordinating power factor limit value at critical point, the upper reaches.

Step S4 upgrades the Control Parameter of AVC system according to the power factor limit value at critical point, electrical network downstream, and according to the reactive power at this Control Parameter regulation and control electrical network critical point.

In one embodiment, whenever the Control Parameter of the critical point power factor of AVC system is once upgraded, the coordinating power factor limit value at critical point, said downstream is made as the Control Parameter setting value of AVC system at a distance from 15 minutes.

Particularly, the step of the reactive power at the said Control Parameter regulation and control of foundation electrical network critical point specifically comprises:

Step S401, the transformer station that monitors lower floor's subnet in real time uprises side critical point power factor.

Step S402, if uprise side critical point power factor in the power factor controlling parameter tuning value scope of AVC critical point, then the AVC system maintains the original state.

Step S403; If uprise the scope that side critical point power factor surpasses AVC critical point power factor controlling parameter tuning value; Then the AVC system will send control signal, and control transformer carries out idle throwing and moves back, and satisfy AVC critical point power factor controlling parameter tuning value scope until uprising side critical point power factor.

In the above-mentioned regulation process; Because adjusting of coordinating power factor both considered the safe operation target call of upper strata major network; The idle regulation and control resource and the load level situation of lower floor's subnet have been taken into account again; So the REACTIVE POWER regulation and control of this regulate and control method between can effective coordination levels electrical network have solved the mismatch problems in levels electric network reactive-load/regulating and controlling voltage.

For clear more technical scheme of the present invention, set forth a application example below based on the electrical network critical point Reactive Power Control method of AVC system.

Should further specify with the real time data section with provincial 500kV electrical network and region 220kV electrical network moment T in the instance, particularly, be elaborated with AB of 500kV transformer station and lower floor section thereof.

The trend calculated data comprises: 500kV props up circuit-switched data, 500kV transformer parameter, active power of sending under the 500kV transformer medium voltage side under the big operational mode of summer and generator output data.

Various constraintss: the bound of each 500kV transformer reactive power compensation amount; The bound of each 500kV transformer gear; The meritorious bound of exerting oneself of each 500kV generating set, the bound of 500kV busbar voltage, virtual power supply do not arrange idle bound of exerting oneself.

Execution in step a～d is according to the objective function F of first Mathematical Modeling _Min.0Carry out optimizing and calculate, under big operational mode of summer, the more tangible a plurality of load level P of the discrimination that provincial power network send under the region electrical network _Always, choose 30000MW respectively, 35000MW, 40000MW; 45000MW, 50000MW, total active power that 55000MW carries as the downward straton net of provincial power network; Calculate the downward straton net of upper strata major network when carrying different total active power, the average power factor limit value at corresponding different critical points, the electrical network upper reaches, province ground is respectively 0.863,0.911; 0.941,0.961,0.977; 0.989, above-mentioned discrete point is carried out match with the curve of smooth and continuous, can work up the relation curve of critical point, the electrical network upper reaches, the province ground average coordinating power factor limit value that load is relevant under the big operational mode of summer.

Fig. 2 shows the relation curve of total active power of being simulated under the big operational mode of provincial power network summer and average coordinating power factor limit value, and this relation curve is quantitatively weighed provincial power network to the maximum idle ability to bear of region electrical network.

The active power of sending under each 500kV transformer medium voltage side of all transformer stations in the monitoring provincial power network calculates the active power P that send under each transformer station's medium voltage side, obtains the average active power P that send under transformer station's medium voltage side in the major network of upper strata _AvWith the maximum active power P that send down _Max, adopt linearization process, obtain critical point, the upper reaches coordinating power factor limit value of each 500kV transformer station; Particularly, with the A of provincial power network transformer station _BAnd the instance explanation is carried out in the lower floor section.

The calculation time T provincial power network A of transformer station _BThe trend situation, at this moment, the A of transformer station in the provincial power network _BThe active power P that medium voltage side is carried to lower floor's electrical network is 2193.2MW; Reactive power Q is 510.2MVar, and critical point, upper reaches power factor is 0.974, and the 500kV of this transformer station busbar voltage is 522.39kV; The 220kV transformer station high-voltage side bus average voltage level of the section B of lower floor is 227.56kV; Medium voltage side bus average voltage level is 114.71kV, and low-pressure side bus average voltage level is 10.37kV, the A of transformer station _BThe section active power loss is 40.40MW, and reactive power loss is 160.48MVar.

The active power P that send under all 500kV transformer station medium voltage sides in the monitoring calculation provincial power network, it is added up obtains P _AlwaysBe 33730.3MW, according to relation curve shown in Figure 2, the lower limit cos θ of the average coordinating power factor at the critical point, the upper reaches that can obtain loading relevant _l=0.902, by formula (4) are not less than 0.95 rigid requirement, then cos θ in order to satisfy " power system voltage and the technological guide rule of var " for transformer critical point power factor _l=0.95.

The active power P that send under all 500kV transformer station medium voltage sides that obtain according to monitoring calculation and total active power P _Always, the average active power that obtains to send under the 500kV transformer station medium voltage side is P _Av=803.1MW, the A of transformer station in the major network of upper strata _BThe active power of sending under the medium voltage side is P to the maximum _Max=2574.4MW obtains cos θ by formula (7) _h=0.99, by formula linearization process is adopted in (6), calculates under big operational mode of summer, at this moment the 500kV A of transformer station _BThe coordinating power factor lower limit at critical point, the upper reaches be cos θ=0.981.

Under big operational mode of summer, the A of provincial power network transformer station _BMaximum active power and the minimum active power under the region electrical network, sent are respectively 2461MW and 1143MW; Monitor the active power of sending under each transformer medium voltage side in the major network of upper strata this moment; The total active power that obtains delivering under the provincial power network transformer station medium voltage side region electrical network that adds up is 44346MW and 21475MW, the A of transformer station ₀Carry the heaviest website of burdens with power for all 500kV transformer stations medium voltage sides, be respectively 2812MW and 2196MW,, calculate the A of transformer station according to relation curve shown in Figure 2 and formula (4), formula (6) _BCritical point, the upper reaches coordinating power factor limit value that corresponding load is relevant is respectively 0.982 and 0.965, and coordinating power factor limit value satisfies under the constraints at critical point, the upper reaches, according to the target function f of second Mathematical Modeling _Lim0Carry out optimizing and calculate, calculate and gain merit when being respectively 2461MW and 1143MW, the limit value of corresponding critical point, downstream coordinating power factor is respectively 0.987 and 0.965.

According to formula (11), calculate critical point, downstream coordinating power factor limit value:

Coordinating power factor limit value with the critical point, downstream

As the A of transformer station _BThe Control Parameter setting value of the AVC critical point power factor of the section B of lower floor is under big operational mode of summer, as the A of transformer station _BThe 220kV transformer station of the section B of lower floor uprises side critical point power factor in the 0.985-1.0 scope time, and the AVC system will be failure to actuate; Instantly the arbitrary 220kV transformer station of synusia district B uprises side critical point power factor outside the 0.985-1.0 scope; Touched AVC system acting condition; The AVC system will send control signal; Carry out idle throwing and move back uprising 220kV transformer station that side critical point power factor surpasses the 0.985-1.0 scope, until uprising till side critical point power factor satisfies said AVC critical point power factor controlling parameter tuning value scope.

The safe operation target that has taken into full account the upper strata major network based on the electrical network critical point Reactive Power Control method of AVC system of the present invention; Calculate through actual upper strata major network being carried out trend; Match also works up the relation curve of the average coordinating power factor limit value at the relevant critical point, the upper reaches of load, with the quantitative idle ability to bear of being held electrical network of having weighed; Otherness to each transformer station's burden with power level of upper strata major network; Adopt linearization technique, the coordinating power factor limit value at each critical point, transformer station upper reaches of differentiation has taken into full account the safe operation target call of upper strata major network; Also take into account simultaneously idle ability of regulation and control and the burden with power level that lower floor's subnet is possessed; Through making up model, carry out trend and calculate, obtain the coordinating power factor limit value at critical point, downstream; The coordinating power factor limit value at the critical point, downstream that obtains adjusting is as AVC critical point power factor controlling parameter tuning value; Facilitate the coordination control of higher level's electrical network and subordinate's electric network reactive-load/regulating and controlling voltage, solved the mismatch problems that electric network reactive-load/regulating and controlling voltage possibly occur, further improve the quality of voltage of electrical network; Reduce via net loss; Alleviate the reactive balance pressure of upper strata major network, thereby guaranteed the safe operation of major network, improved the safety and stability economical operation of electrical network.

Through analyzing the data in the above-mentioned application example, compare the A of 500kV transformer station respectively below _BThe voltage levvl situation of lower floor section, power loss situation and reactive power are striden emotionally condition of laminar flow, comprise following three kinds of ruuning situations:

(1) A of 500kV transformer station _BThe trend situation of lower floor's section actual motion;

According to the A of 500kV transformer station _BAnd lower floor's electrical network, the equivalent medium voltage side of load in 220kV transformer station, according to T trend section situation constantly, the switching through to the reactive power compensation of 220kV transformer station can initial fitting go out the transformer station A approaching with actual electric network ruuning situation _BThe trend situation of section, the i.e. A of transformer station _BHigh side voltage is 522.39kV, and it is 6 grades that gear is adjusted, the A of 500kV transformer station _BThe active power of sending under the medium voltage side is about 2193.2MW, and reactive power is about 510.2MVar, and with it as initial situation, table 1 is the A of transformer station _BThe analysis tabulation of section trend situation;

Table 1

(2) under the existing idle control technique, the A of 500kV transformer station _BThe trend situation of lower floor section;

AVC critical point power factor controlling parameter tuning is along with the 220kV busbar voltage is done stage floating; When 220kV transformation station uprises side critical point power factor above setting range; The AVC system will control the throwing of reactive power compensation automatically and move back; Up to uprise side critical point power factor in setting range or do not had can throw idle resource till, abbreviate existing idle control technique as; Table 2 is made stage unsteady typical critical point power factor for existing with the 220kV busbar voltage, and table 3 is under the existing idle control technique, the A of transformer station _BThe trend situation analysis tabulation of section;

Table 2

220kV transformer critical point busbar voltage/kV	220kV transformer critical point uprises the side power factor
		＜220	0.97-(-0.99)
220-223	0.96-1.0
		223-233	0.95-1.0
233-236	0.94-0.97
		＞236	0.90-0.95

Table 3

(3) under the inventive method, the A of 500kV transformer station _BThe trend situation of lower floor section;

AVC critical point power factor controlling parameter tuning is according to the result of calculation of economizing critical point, electrical network downstream, ground coordinating power factor limit value; When 220kV transformation station uprises side critical point power factor above setting range; The throwing of AVC system control reactive power compensation is moved back; Up to uprise side critical point power factor in setting range or do not had can throw idle resource till, according to the electrical network critical point Reactive Power Control method based on the AVC system of the present invention, abbreviate the inventive method as; Economizing critical point, the electrical network upper reaches, ground coordinating power factor lower limit is 0.981, and economizing critical point, electrical network downstream, ground coordinating power factor lower limit is 0.985, so AVC critical point power factor controlling parameter tuning value is 0.985-1.0, table 4 is the A of transformer station in the inventive method _BThe trend situation analysis tabulation of section;

Table 4

Compare with existing idle control technique and practical operation situation, adopt method of the present invention can effectively improve the A of 500kV transformer station _BThe trend distribution situation of lower floor section.

To shown in Figure 5, show the trend contrast situation of practical operation situation (X1), the inventive method (X2), existing idle control technique (X3) referring to Fig. 3 among the figure respectively.

1) Fig. 3 shows: the A of 500kV transformer station _BThe average voltage of lower floor's section 220kV transformer high-voltage side bus brings up to 228.92 from 223.54kV; The average voltage of medium voltage side bus is brought up to 115.61kV from 111.92kV; Low-pressure side bus voltage is brought up to 10.47kV from 10.11kV, and the quality of voltage level has had bigger lifting; Practical operation situation with match is compared, the A of transformer station _BThe average voltage of section 220kV transformer station high-voltage side bus is mentioned 228.92kV from 227.56kV; The average voltage of medium voltage side bus is brought up to 115.61kV from 114.71kV; Low-pressure side bus voltage is brought up to 10.47kV from 10.37kV, and quality of voltage also has a certain upgrade;

2) Fig. 4 shows: the A of 500kV transformer station _BThe active power loss of lower floor section drops to 39.92MW from 42.04MW, and reactive power loss drops to 146.08MVar from 208.41MVar, and the effect of saving energy and decreasing loss is obvious; Practical operation situation with match is compared, the A of transformer station _BThe active power loss of section drops to 39.92MW from 40.40MW, and reactive power loss drops to 146.08MVar from 160.48MVar, the saving energy and decreasing loss better effects if;

3) Fig. 5 shows: under big operational mode of summer, the idle amount of lower floor's region electrical network provincial power network demand from the upper strata drops to 425.81MVar from 727.92MVar, has further alleviated the reactive balance pressure of upper strata major network; Practical operation situation with match is compared; Under big operational mode of summer; The idle amount of lower floor's subnet major network demand from the upper strata drops to 425.81MVar from 510.20MVar, has further reached the controlled target of idle layering and zoning in-situ balancing, has alleviated the pressure of the reactive balance of upper strata major network.

The above embodiment has only expressed several kinds of execution modes of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to claim of the present invention.Should be pointed out that for the person of ordinary skill of the art under the prerequisite that does not break away from the present invention's design, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection range of patent of the present invention should be as the criterion with accompanying claims.

Claims (10)

1. the electrical network critical point Reactive Power Control method based on the AVC system is characterized in that, comprises the steps:

According to the trend calculated data constraints of electrical network, obtain the relation curve between total active power of sending under the critical point, the upper reaches and the corresponding average coordinating power factor limit value;

Monitor the active power of sending under each the transformer medium voltage side in the major network of upper strata in real time, and calculate critical point, the upper reaches coordinating power factor limit value of each transformer station according to said relation curve;

Calculate the coordinating power factor limit value at critical point, downstream according to critical point, said upper reaches coordinating power factor limit value;

Upgrade the Control Parameter of AVC system according to the power factor limit value at critical point, said electrical network downstream, and according to the reactive power at said Control Parameter regulation and control electrical network critical point.

2. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 1 is characterized in that said trend calculated data comprises: a circuit-switched data, transformer parameter, various operational mode loads and generator output data;

Said constraints comprises: control variables constraints and state variable constraints; Wherein, control variables constraints comprises that generator reactive goes out the force vector bound, the maximum reactive power compensation vector of transformer bound, transformer tapping gear vector bound; State variable constraints comprises busbar voltage amplitude vector bound, and virtual power supply is not arranged the idle force vector bound that goes out.

3. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 1 is characterized in that, the said step of obtaining the relation curve between the active power sent under the critical point, the upper reaches and the corresponding average coordinating power factor limit value specifically comprises:

Set up first Mathematical Modeling of the average coordinating power factor limit value at critical point, the upper reaches; Wherein, this Mathematical Modeling is used for calculating the average coordinating power factor limit value at the critical point, the upper reaches of satisfying said constraints according to the load level under the operational mode of setting;

According to said first Mathematical Modeling, when calculating the downward straton net conveying of upper strata major network different active power, the average power factor limit value at critical point, the corresponding upper reaches;

Simulate the relation curve between the average coordinating power factor limit value at active power that major network downward straton net in upper strata carries and corresponding critical point, the upper reaches according to said average power factor limit value.

4. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 3 is characterized in that said first Mathematical Modeling comprises formula:

minf(Q _1G，T _1K，Q _1C)＝F _min.0

s.t.h(Q _1G，T _1K，Q _1C)＝0

$\left\{\begin{array}{c}{Q}_{1\mathrm{GL}}\≤Q_{1G}\≤Q_{1\mathrm{GH}}\\ T_{1\mathrm{KL}}\≤T_{1K}\≤T_{1\mathrm{KH}}\\ Q_{1\mathrm{CL}}\≤Q_{1C}\≤Q_{1\mathrm{CH}}\\ V_{1\mathrm{BL}}\≤V_{1B}\≤V_{1\mathrm{BH}}\\ Q_{1\mathrm{ZL}}\≤Q_{1Z}\≤Q_{1\mathrm{ZH}}\end{array}\right.$

In the formula, F _Min.0Be target function, Q _1G, T _1K, Q _1CBe the control variables of upper strata major network transformer station, wherein Q _1GExpression generator idle goes out force vector, T _1KRepresent each transformer tapping gear vector, Q _1CReactive power compensation vector for each transformer; V _1BAnd Q _1ZBe state variable, V wherein _1BThe voltage magnitude vector of each bus of expression upper strata major network transformer station, Q _1ZFor virtual power supply is not arranged the idle force vector that goes out; Subscript L and H represent the lower limit and the higher limit of relevant variable respectively.

5. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 4; It is characterized in that; Said according to said first Mathematical Modeling; When calculating the downward straton net conveying of upper strata major network different active power, the step of the average power factor limit value at critical point, the corresponding electrical network upper reaches specifically comprises:

According to trend calculated data constraints, calculate the active power of sending under each transformer station's medium voltage side, said active power summation is obtained the downward straton net of upper strata major network carry the total power value of active power;

The generating set that capacity in the major network of upper strata is maximum is made as the balance node of the whole network, and the transformer station that chooses the HVDC drop point is as not arranging the idle website of exerting oneself;

Preset all transformer medium voltage side power factors are identical initial value, and this initial value is made as the initial value of the average coordinating power factor limit value at critical point, the upper reaches;

According to the initial value and the Ge Tai transformer medium voltage side active power of said average coordinating power factor limit value, revise the reactive power of transformer medium voltage side, carry out trend then and calculate;

According to the constraints in the said Mathematical Modeling, judge said trend result calculated, obtain the upper strata major network under different operational modes, the average coordinating power factor limit value that said total power value is corresponding.

6. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 1; It is characterized in that; The active power of sending under each transformer medium voltage side in the major network of said real-time monitoring upper strata, and specifically comprise according to the step that said relation curve calculates critical point, the upper reaches coordinating power factor limit value of each transformer station:

Monitor the active power of sending under each transformer medium voltage side in the major network of upper strata respectively, and calculate total active power, obtain the average coordinating power factor limit value at the upper reaches critical point corresponding according to said relation curve with this total active power;

According to the active power of sending under each transformer medium voltage side in the upper strata major network of said monitoring, obtain average active power and the maximum active power sent under transformer station's medium voltage side in the major network of upper strata;

According to said average active power and maximum active power the active power of sending under said each transformer station's medium voltage side is carried out linearization process, obtain corresponding critical point, the upper reaches coordinating power factor limit value of each transformer station in the major network of upper strata;

Wherein, the process of said linearization process comprises formula:

$\cos \mathrm{\θ}=\left\{\begin{array}{cc}\frac{P-P_{\mathrm{av}}}{P_{\max }-P_{\mathrm{av}}}(\cos {\mathrm{\θ}}_h-\cos {\mathrm{\θ}}_l)+{\cos \mathrm{\θ}}_l& P>P_{\mathrm{av}}\\ \cos {\mathrm{\θ}}_l& P\≤P_{\mathrm{av}}\end{array}\right.$

In the formula, P is the active power of sending under transformer station's medium voltage side, cos θ _lBe the average coordinating power factor limit value at critical point, the upper reaches, P _AvBe the average active power that send under transformer station's medium voltage side, P _MaxBe the maximum active power of sending under transformer station's medium voltage side, cos θ _hBe the lowest power factor that the heaviest substation's permission of medium voltage side load is sent down, cos θ is the coordinating power factor limit value at critical point, the upper reaches.

7. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 1 is characterized in that, the said step of calculating the coordinating power factor limit value at critical point, downstream according to critical point, said upper reaches coordinating power factor limit value specifically comprises:

Set up second Mathematical Modeling of the average coordinating power factor limit value at critical point, downstream; Wherein, this Mathematical Modeling is used for calculating the average coordinating power factor limit value at the critical point, downstream of satisfying said constraints according to the load level under the operational mode of setting;

Under the operational mode of setting, according to the trend section that send maximum active power and minimum active power under transformer station's medium voltage side, the active power of sending under each transformer medium voltage side in the major network of monitoring upper strata;

According to relation curve and critical point, the upper reaches coordinating power factor limit value between total active power of sending under the critical point, the said upper reaches and the corresponding average coordinating power factor limit value, obtain the coordinating power factor limit value that send the corresponding critical point, the upper reaches of maximum active power and minimum active power under the said transformer station medium voltage side respectively;

According to said second Mathematical Modeling, calculate the coordinating power factor limit value at the critical point, downstream of sending maximum active power and minimum active power correspondence under the said transformer station medium voltage side;

According to the coordinating power factor limit value that send the corresponding critical point, the upper reaches of maximum active power and minimum active power under the said transformer station medium voltage side; And the coordinating power factor limit value that gives the critical point, downstream of maximum active power and minimum active power correspondence under the said transformer station medium voltage side, calculate the coordinating power factor limit value at critical point, downstream.

8. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 7 is characterized in that said second Mathematical Modeling comprises formula:

minf(Q _2G，T _2K，Q _2C)＝f _lmin.0

s.t.h(Q _2G，T _2K，Q _2C)＝0

$\left\{\begin{array}{c}{Q}_{2\mathrm{GL}}\≤Q_{2G}\≤Q_{2\mathrm{GH}}\\ T_{2\mathrm{KL}}\≤T_{2K}\≤T_{2\mathrm{KH}}\\ Q_{2\mathrm{CL}}\≤Q_{2C}\≤Q_{2\mathrm{CH}}\\ V_{2\mathrm{BL}}\≤V_{2B}\≤V_{2\mathrm{BH}}\\ \cos {\mathrm{\θ}}_0\≥\cos \mathrm{\θ}\≤\end{array}\right.$

In the formula, f _Lim.0Be target function, Q _2G, T _2KAnd Q _2CBe the control variables of subnet transformer station of lower floor, wherein Q _2GThe expression generator reactive goes out force vector, T _2KThe tap gear vector of representing each transformer, Q _2CBe the reactive power compensation vector of each transformer, V _2BWith cos θ be state variable, V wherein _2BThe voltage magnitude vector of expression lower floor subnet substation bus bar, cos θ is the coordinating power factor limit value at critical point, the upper reaches, cos θ ₀Be the power factor at real-time critical point, the upper reaches of monitoring, subscript L and H represent the lower limit and the higher limit of relevant variable respectively;

The process of the coordinating power factor limit value at critical point, said calculating downstream comprises formula:

In the formula,

Be the coordinating power factor limit value at critical point, downstream, cos θ is when sending active power P under transformer station's medium voltage side, the coordinating power factor limit value at critical point, the upper reaches, cos θ _HWith cos θ _LBe respectively the coordinating power factor limit value at the critical point, the upper reaches of sending maximum active power and minimum active power correspondence under transformer station's medium voltage side,

With

Be respectively the coordinating power factor limit value at the critical point, downstream of sending maximum active power and minimum active power correspondence under transformer station's medium voltage side.

9. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 1; It is characterized in that; The step of upgrading the Control Parameter of AVC system according to the power factor limit value at critical point, said electrical network downstream specifically comprises: whenever at a distance from 15 minutes the Control Parameter of the critical point power factor of AVC system is once upgraded, the coordinating power factor limit value at critical point, said downstream is made as the Control Parameter setting value of AVC system.

10. the electrical network critical point Reactive Power Control method based on the AVC system according to claim 1 is characterized in that, the step of the reactive power at the said Control Parameter regulation and control of said foundation electrical network critical point specifically comprises:

The transformer station of the lower floor of monitoring in real time subnet uprises side critical point power factor;

If the said side critical point power factor that uprises is in the power factor controlling parameter tuning value scope of AVC critical point, then the AVC system is failure to actuate;

If the said scope that uprises side critical point power factor above AVC critical point power factor controlling parameter tuning value; Then the AVC system will send control signal; Control transformer carries out idle throwing and moves back, and satisfies said AVC critical point power factor controlling parameter tuning value scope until the said side critical point power factor that uprises.

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