CN103457297A - Closed-loop control method for achieving active power adjustment by introducing frequency deviation feedback to have control over voltage - Google Patents

Abstract

The invention relates to a closed-loop control method for achieving active power adjustment by introducing frequency deviation feedback to have control over voltage, and an obtaining method of an optimal feedback gain parameter in the closed-loop control method. According to the closed-loop control method for achieving active power adjustment by introducing the frequency deviation feedback to have control over the voltage, due to the facts that an isolated power grid has the characteristics that the active power adjustment capacity is not sufficient, and a special load characteristic of a rectification load exists, the load power is adjusted through a method for adjusting voltage of a load bus, and the frequency deviation is introduced into an excitation regulator to serve as feedback input, a voltage closed-loop control method based on frequency information is achieved. Unbalanced power which exists after a system fault happens is distinguished through a WAMS system in an on-line mode, and a WAMS voltage closed-loop control optimal feedback gain parameter is calculated in an on-line mode on the basis of the load characteristic and a voltage sensitivity method and in the mode that the primary frequency adjustment capacity of a generating unit is taken into account. The effectiveness of the obtaining method of the optimal feedback gain parameter and the effectiveness of the closed-loop control method for achieving active power adjustment by introducing frequency deviation feedback to have control over the voltage are verified through RTDS simulation.

Description

Pull-in frequency deviation FEEDBACK CONTROL voltage is realized the meritorious closed loop control method of regulating

Technical field

The present invention relates to a kind of closed loop control method, especially relate to a kind of pull-in frequency deviation FEEDBACK CONTROL voltage and realize the meritorious closed loop control method of regulating.

Background technology

Energy centre and load center present the area of serious contrary distribution, and main manifestations is that most energy resources are distributed in the northwestward, and the energy demand more than 70% concentrates on the middle part, east.Traditional solution thinking is to solve by ultra high voltage and superhigh pressure long distance power transmission.In fact, relying on the mode of setting up micro-electrical network is a kind of very effectively solution route by the highly energy-consuming industry at power center's on-site elimination.

The system islet operation can be realized that enterprise brings huge economic benefit, but has brought stern challenge also to the safe and stable operation of system simultaneously.Traditional large electrical network has numerous fired power generating unit.When system is received power disturbance, because the system moment of inertia is large, and generating set is numerous, and system can be passed through traditional primary frequency modulation and frequency modulation frequency modulation responding power disturbance, maintains the frequency of system and voltage in the fluctuation allowed band.In addition, large network load is differential numerous, therefore can select the load of capacity suitable to excise fast, thereby eliminate imbalance power rapidly.Yet for the similar electrolytic aluminium this high energy-consuming industry of loading, because load configuration is differential single, therefore can be whether limited for the load of system excision.Only rely on the mode of connection cutting load, be difficult to eliminate fully original paper fault or the caused imbalance power of wind power disturbance due to system.The island network small scale, the system equivalent moment of inertia is little, thereby, under the load power fluctuation, system frequency is short transit time.In sum, for load, be the island network of similar this class of electrolytic aluminium, can't guarantee the safe and stable operation of system iff the FREQUENCY CONTROL means by traditional, need to propose the safe and stable operation that high-precision control method guarantees island network.

Be similar to electrolytic aluminium this class electrolysis class industry of loading, technological principle is that direct current passes into electrolysis tank, and electrochemical reaction occurs at the aluminium oxide yin, yang the two poles of the earth in groove that make to be dissolved in electrolyte.Load is subject to the impact of system frequency hardly, there is no the primary frequency modulation characteristic of conventional load, but has the close coupling relation with the voltage of load bus.In order fully to excavate the fm capacity of island network, solve the situation of island network frequency modulation means deficiency, need to study frequency and voltage control method for coordinating fast and effectively.

Summary of the invention

The pull-in frequency deviation FEEDBACK CONTROL voltage of the invention is realized the meritorious closed-loop control of regulating.The method utilizes the rectification load to have stronger these characteristics of voltage-regulation characteristic, meritorious regulating power in system is subject in limited time, fully excavate the fm capacity of load, consider the active power of the voltage-regulation rectification load by regulating rectification load bus, realize the frequency stabilization of system.On the basis of original automatic excitation adjustor of generator, utilize the acquisition system frequency of PMU real-time high-precision, the positive feedback using the frequency departure amount as the field regulator reference voltage, realize frequency-voltage real-time closed-loop control, the imbalance power that the elimination system exists.

Above-mentioned technical problem of the present invention is mainly solved by following technical proposals:

A kind of pull-in frequency deviation FEEDBACK CONTROL voltage is realized the meritorious closed loop control method of regulating, and it is characterized in that comprising the following steps:

Step 1, the power disturbance size of utilizing WAMS (WAMS) real-time monitoring system to be subject to and the stand-by heat amount of capacity of system, obtain thereby calculate the two difference the imbalance power Δ P that system exists.

The computing formula of imbalance power is:

ΔP=P _step-P _reserve

Wherein, Δ P means the imbalance power of system, P _stepfor the power disturbance value that system is subject to, its value can be monitored by WAMS, P _reservefor the spinning reserve of system, its value also can be monitored by WAMS.

Step 2, according to the ratio of the capacity of aluminium manufacturer load, the system imbalance power of measuring is carried out to reasonable distribution, suppose that island network has i load point, calculating this i load point according to this allocation rule needs respectively the load reduced, and then utilizes the model parameter of the rectification load that IEEE load modeling working group recommends to calculate the voltage adjustment amount of the busbar voltage of each load point.

The Mathematical Modeling of the rectification load that IEEE load modeling working group is recommended is:

$P=P_N{\left(\frac{U}{U_N}\right)}^{1.8}{\left(\frac{f}{f_N}\right)}^{-0.3}$

Wherein, P _n, U _n, f _nbe respectively rated power, voltage, the frequency of rectification load bus, P, U, f are respectively actual power, voltage, the frequency of rectification load bus.

The voltage adjustment amount computing formula of the busbar voltage of each load point is as follows:

Wherein, Δ U _lithe voltage adjustment amount that means i rectification load, U _before, U _afterthe voltage of i rectification load before and after meaning respectively to adjust, P _before, P _afterthe power of i rectification load before and after meaning respectively to adjust, mean the voltage that i rectification loaded.

Step 3, utilize the method for voltage sensibility analysis to ask for voltage sensibility matrix and the electrical distance matrix of system, thereby draw the relation between load bus voltage variety and power generator electrode terminal voltage variable quantity.And, according to the busbar voltage reduction value of each load bus of obtaining in step 2, can calculate the voltage adjustment amount of the set end voltage of each fired power generating unit.

Concrete methods of realizing is: the voltage sensibility matrix and the electrical distance matrix that at first calculate system, then utilize the electrical distance matrix calculated to find out the nearest load bus of each fired power generating unit electrical distance, the voltage adjustment amount that the load bus that finally utilization calculates and the voltage sensibility between the generator node calculate the generator node.

Step 4, utilize the unit power regulation of the remaining meritorious pondage of fired power generating unit and fired power generating unit to calculate the frequency departure of system, then utilize the voltage adjustment amount of each fired power generating unit set end voltage that step 3 calculates to calculate the gain parameter of the frequency departure feedback element of each fired power generating unit excitation system.

In the situation that system imbalance power and difference coefficient are known, can calculate the frequency departure of system, computing formula is as follows:

${\mathrm{\&Delta;P}}_G=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&Delta;P}}_{\mathrm{Gi}}=-\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{K}_{\mathrm{Gi}}\&CenterDot;\mathrm{\&Delta;f}=-\underset{i=1}{\overset{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="HDA00003505610800012.png,HDA00003505610800021.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}\frac{1}{{\mathrm{\&sigma;}}_{i*}}\&CenterDot;\frac{P_{\mathrm{GiN}}}{f_N}\&CenterDot;\mathrm{\&Delta;f}$

Wherein, Δ P _gthe reserve capacity that means the island network system, K _githe power of each fired power generating unit-frequency static characteristic coefficient in expression island network system, also referred to as unit power regulation, σ _i*the difference coefficient that means each fired power generating unit in the island network system, P _giNspecified active power for each fired power generating unit.

The frequency departure that utilization calculates and set end voltage adjustment amount can calculate the gain parameter of the frequency departure feedback element of each fired power generating unit excitation system, and computing formula is as follows:

K _i·Δf=ΔU _Gi

Wherein, the frequency departure that Δ f is system, Δ U _gibe the set end voltage adjustment amount of i platform fired power generating unit, K _iit is the frequency departure feedback oscillator parameter of i platform fired power generating unit.

Step 5, utilize the gain parameter value of the frequency departure feedback element of determined each fired power generating unit excitation system of step 4, pull-in frequency deviation feedback is as the input of excitation system excitation reference voltage link, thereby realizes that frequency-voltage coordinates to control.Conventional field regulator is all the input using the set end voltage of generator as field regulator, thereby realizes the reactive power adjusting of generator.This paper, on the basis of original automatic excitation adjustor of generator, utilizes the acquisition system frequency of PMU real-time high-precision, using frequency departure amount Δ f as field regulator reference voltage V _refpositive feedback, realize that frequency-voltage real-time closed-loop controls, thereby be subject to, fully to excavate the fm capacity of load in limited time, the imbalance power that the elimination system exists in system frequency modulation means.

When system enters urgent running status, need by the load mode of busbar voltage level of sacrifice, the quick adjustment load power, thus stabilize the imbalance power existed in island network.Voltage-controlled purpose now be not traditional voltage levvl that maintains in the fluctuation allowed band, thereby but regulate load power according to voltage character of load control overhead node voltage, with the imbalance power existed in the elimination system.As shown in Figure 6, when system emergent power vacancy causes frequency to descend, frequency deviation f can reduce the set end voltage reference value in field regulator, thereby reduces the output of field regulator, reduces the idle output of generator.Therefore, load bus voltage can descend, thereby causes load power to reduce, until system finds new balance point.

Therefore, the present invention has following advantage: can regulate fast and effectively load power, maintain the frequency stabilization of island network.Utilize the imbalance power of WAMS systematic survey island network system, and calculate the gain parameter of frequency departure feedback element by the method for voltage sensibility analysis, realized that the coordination of frequency and voltage is controlled.The method, for the meritorious very limited characteristics of regulating power of the island network of highly energy-consuming rectification load and fired power generating unit cooperation, has proposed novel and effective voltage to frequency control method for coordinating, has good promotional value and application prospect.

The accompanying drawing explanation

The network structure of Fig. 1 island network system.

Fig. 2 is former excitation system block diagram.

Fig. 3 is the closed-loop control excitation system block diagram of pull-in frequency deviation feedback.

Fig. 4 is the frequency response curve analogous diagram of taking system after novel closed loop control method.

Fig. 5 is the voltage response curves analogous diagram of taking three load buses after novel closed loop control method.

Fig. 6 is the field regulator structural representation of pull-in frequency deviation FEEDBACK CONTROL involved in the present invention.

Embodiment

Below by embodiment, and by reference to the accompanying drawings, technical scheme of the present invention is described in further detail.

Embodiment:

Below in conjunction with drawings and Examples, technical scheme of the present invention is further illustrated.

One, the voltage sensibility matrix of computing system and electrical distance matrix

1. sensitivity matrix refers to and derives on the basis of electric power system tide equation, it is not the simple combination of each node sensitivity in system, be actually improvement and the distortion of Jacobian matrix, the character of sensitivity matrix can be used for studying many practical problems of field of power.Usually, the power flow equation of electric power system can be expressed as simply:

f(x,u)=0 (1)

Wherein x is state variable, and u is control variables, and when system, under certain operational mode during stable operation, the power flow equation of system can be expressed as:

f(x ₀,u ₀)=0 (2)

Wherein, (x ₀, u ₀) be illustrated in the steady operation point under this operational mode, when this steady operational status is subject to microvariations, there is a deviation delta x in state variable, and also there is a deviation delta u in control variables, and now the power flow equation of system can be expressed as:

f(x ₀+Δx,u ₀+Δu)=0 (3)

By formula (5) at steady operation point (x ₀, u ₀) locate linearisation, can obtain formula (4) as follows:

$f(x_0,u_0)+\frac{\&PartialD;f}{\&PartialD;x}\mathrm{\&Delta;x}+\frac{\&PartialD;f}{\&PartialD;u}\mathrm{\&Delta;u}=0---\left(4\right)$

Learn that according to formula (2) formula (4) can be rewritten as following form:

$\frac{\&PartialD;f}{\&PartialD;x}\mathrm{\&Delta;x}+\frac{\&PartialD;f}{\&PartialD;u}\mathrm{\&Delta;u}=0---\left(5\right)$

The basic representation that formula (5) is the system sensitivity equation, the matrix in formula

with

be called Jacobian matrix, when

when nonsingular, the linear relation of state variable deviation and control variables deviation is:

$\mathrm{\&Delta;x}=-{\left(\frac{\&PartialD;f}{\&PartialD;x}\right)}^{-1}\frac{\&PartialD;f}{\&PartialD;u}\mathrm{\&Delta;u}=\mathrm{S\&Delta;u}---\left(6\right)$

Formula in (6) is

the sensitivity matrix that is called system.

What voltage sensibility meaned is the sensitivity relation of a kind of load bus voltage to each control variables of system, can reflect the power of control variables to the voltage control capability of load bus.Electric power system is normally in service, and on less time scale, it is proportional that the voltage magnitude of each node changes,

ΔU _i=a _ijΔU _j(i,j∈S) (7)

In formula (7), the set that S is all nodes in system, a _ijfor Δ U _iwith Δ U _jsensitivity relation,

Its definition is as follows:

$a_{\mathrm{ij}}=\frac{{\&PartialD;U}_i}{\&PartialD;Q_j^{\&prime;}}/\frac{\&PartialD;U_j}{\&PartialD;Q_j^{\&prime;}}---\left(8\right)$

In formula (8)

with

for the inverse matrix of Jacobian matrix B'', it is to have the sensitivity matrix of similar quality with the network impedance matrix, means that the change in voltage magnitude relationship between each node is called the voltage sensibility analysis.

2. in system, the electrical distance size between each node can reflect the power of the electrical link between node.Electrical distance between node can be expressed as:

d _ij=-log(a _ija _ji) (9)

According to the voltage sensibility analysis theories, know, in the situation that trend convergence, if we know the voltage variety of a node, just can calculate the voltage variety of other node according to the pressure sensitive relation between each node calculated so, but because our meter sensitivity matrix is to carry out under the prerequisite of simplifying, we can consider by and the near node of required node electrical distance between sensitivity relation try to achieve the variable quantity of node voltage, concrete innovation representation is as follows:

$\mathrm{\&Delta;}{U}_i=\underset{j\&Element;S_1}{\mathrm{\&Sigma;}}\frac{a_{\mathrm{ij}}\mathrm{\&Delta;}{U}_j}{d_{\mathrm{ij}}}/\underset{j\&Element;{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00003505610800012.png,HDA00003505610800021.png"\; state="\{\{state\}\}">S</figure-callout>}}_1}{\mathrm{\&Sigma;}}\frac{1}{d_{\mathrm{ij}}}---\left(10\right)$

In formula (10), S ₁mean to be less than with required node electrical distance the node set of a certain threshold value.

In the situation that system parameters is known, voltage sensibility matrix and the electrical distance matrix of island network all can calculated off-line go out, calculate typical sensitivity matrix and electrical distance matrix, realize quick On-line matching when when breaking down, need to take control strategy.

Two, the measurement distribution of the imbalance power of system and load bus voltage adjustment amount computational methods

1. utilize the power disturbance size of synchronous phase angle measuring unit (PMU) real-time acquisition system of WAMS (WAMS) and the meritorious pondage of system, pass through computing unit and calculate the imbalance power that the two difference obtains system.According to certain allocation rule, the system imbalance power of measuring is carried out to reasonable distribution, suppose that island network has i load point, each need to reduce how many loads to calculate this i load point according to certain rule, then utilizes the model parameter of the rectification load that IEEE load modeling working group recommends to calculate the voltage adjustment amount Δ U of the busbar voltage of each load point _li.Suppose to be distributed according to the weight coefficient of the rated load power of each rectification load, voltage adjustment amount Δ U of each load bus _licalculating formula be:

$\mathrm{\&Delta;}{P}_i=C_i\&CenterDot;\mathrm{\&Delta;P}=\frac{P_i}{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_i}\&CenterDot;\mathrm{\&Delta;P}({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HDA00003505610800012.png,HDA00003505610800021.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA00003505610800011.png,HDA00003505610800031.png"\; state="\{\{state\}\}">C</figure-callout>}}_2+\&CenterDot;\&CenterDot;\&CenterDot;+C_n=1,i=\mathrm{1,2,3}\&CenterDot;\&CenterDot;\&CenterDot;n)---\left(11\right)$

In formula (11), Δ P is the imbalance power that the PMU measurement mechanism is measured, P _ifor the rated load power of each rectification load, C _ifor the weight coefficient of each rectification load, Δ P _iactive power adjustment amount for each rectification load.

Under normal operation, the imbalance power of island network system can be measured in real time by the PMU measuring unit, and the load power of each rectification load is given value, and then can obtain the active power adjustment amount Δ P of each rectification load _i.

2.IEEE the part throttle characteristics model of the electrolytic aluminium that load modeling working group is recommended load is as the formula (12):

$P=P_N{\left(\frac{U}{U_N}\right)}^{1.8}{\left(\frac{f}{f_N}\right)}^{-0.3}---\left(12\right)$

According to formula (12), rectification load is meritorious-the frequency adjustment regulating characteristics is for negative, but it is meritorious-and the voltage-regulation characteristic is larger.Utilize the active power adjustment amount Δ P of the load bus of formula (11) calculating _ican derive the voltage adjustment amount Δ U of load bus with the part throttle characteristics expression formula (12) of electrolytic aluminium load _li, suppose that the initial voltage of rectification load bus is U _li, the voltage adjustment amount of rectification load bus is Δ U _li, the adjustment preload size of rectification load is P _before, voltage is U _before, adjusting the afterload size is P _after, voltage is U _after, the voltage adjustment amount derivation of asking for so the rectification load bus is as follows:

Formula (14) can be obtained to formula (15) divided by formula (13) and through distortion:

Through type (15) can calculate the voltage adjustment amount Δ U of each rectification load _lifor:

Three, the computational methods of generator terminal voltage adjustment amount

The voltage sensibility matrix and the electrical distance matrix that utilize step 2 to calculate, can computing system in the set end voltage adjustment amount size of generator.Can calculate each load bus voltage adjustment amount Δ U according to formula (16) _li, then, according to the electrical distance matrix calculated, determine the load bus nodes strong with fired power generating unit relevance to be asked, thereby ask for the variation delta U of generator terminal voltage _gj, concrete methods of realizing is: the electrical distance of obtaining Generator end and electrolytic aluminium load bus nodes.Set the threshold values of electrical distance, when the electrical distance of load bus nodes and Generator end node is less than set threshold values, think that generator voltage is relevant with this load bus change in voltage.Through type (10) and asked for the voltage sensibility value, calculate the set end voltage adjusted value of generator node to be asked, and can accurately ask for by this method the target adjusted value of generator node set end voltage.

Four, the frequency departure feedback oscillator calculation method of parameters of fired power generating unit excitation system

1. calculate the frequency deviation f of system.For island network, Δ f need meet frequency stabilization constraint Δ f<1.5Hz, on this basis, if Δ f is less than normal, the reserve capacity of fired power generating unit can not rely on the primary frequency modulation of fired power generating unit to give full play of, and causes aluminium load needs to reduce more active power.Therefore, the frequency deviation f of system should can calculate by the full entry primary frequency modulation according to the fired power generating unit reserve capacity, by formula (17), is calculated.

${\mathrm{\&Delta;P}}_G=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&Delta;P}}_{\mathrm{Gi}}=-\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{K}_{\mathrm{Gi}}\&CenterDot;\mathrm{\&Delta;f}=-\underset{i=1}{\overset{\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="HDA00003505610800012.png,HDA00003505610800021.png"\; state="\{\{state\}\}">n</figure-callout>}}{\mathrm{\&Sigma;}}}\frac{1}{{\mathrm{\&sigma;}}_{i*}}\&CenterDot;\frac{P_{\mathrm{GiN}}}{f_N}\&CenterDot;\mathrm{\&Delta;f}---\left(17\right)$

In formula (17), Δ P _gthe reserve capacity that means the island network system, K _githe power of each fired power generating unit-frequency static characteristic coefficient in expression island network system, also referred to as unit power regulation, σ _i*the difference coefficient that means each fired power generating unit in the island network system, P _giNspecified active power for each fired power generating unit.

2. calculate pull-in frequency deviation feedback optimum gain parameter K _i.When system enters urgent running status, need by the load mode of busbar voltage level of sacrifice, the quick adjustment load power, thus stabilize the imbalance power existed in island network.Voltage-controlled purpose now be not traditional voltage levvl that maintains in the fluctuation allowed band, thereby but regulate load power according to voltage character of load control overhead node voltage, with the imbalance power existed in the elimination system.The present invention, on the basis of original automatic excitation adjustor of generator, utilizes the acquisition system frequency of PMU real-time high-precision, using frequency departure amount Δ f as field regulator reference voltage V _refpositive feedback, thereby realize that frequency-voltage real-time closed-loop controls.Fig. 2 is the field regulator model obtained in the investigation of field regulator manufacturer, and Fig. 3 is the model that the field regulator of pull-in frequency deviation feedback in this paper is controlled.According to Fig. 3,, the adjustment amount of generator voltage can be expressed as:

K _i·Δf=ΔU _Gi (18)

Voltage variety Δ U according to the generator node calculated _gjwith the frequency deviation f of island network system, just can draw excitation system feedback element gain parameter K _isize.

Five, closed loop control method validity check

Set up the Closed-loop Excitation system of pull-in frequency deviation feedback and carry out the emulation verification on the basis of the island network system model of originally building.Under the conventional operation mode, total active power of system is 1800MW, and system reserve capacity is 135MW.4.0 a second generator of generation is cut the machine accident, No. 6 fired power generating unit that excision rated power is 300MW, meritorious exerting oneself as 278MW before No. 6 fired power generating unit accidents, after accident system loss 278MW active power, meanwhile, the reserve capacity of system has also been lost 22MW, the standby 113MW of system now, the imbalance power of island network system is 165MW, the system reserve deficiency, frequency of occurrences collapse and voltage collapse accident, within after the consideration accident 0.1 second, add the novel closed loop control method of this paper, it is the closed loop control method of the Novel excitation system of pull-in frequency deviation delta f, by in the excitation system model of seven fired power generating unit of the frequency deviation f of island network system introducing island network, Fig. 4 is the frequency response curve of taking system after novel closed loop control method.

As can be seen from Figure 4 and Figure 5, after taking novel closed loop control method, the frequency of island network system and voltage can return in normal range of operation, wherein the frequency of system is reduced to 49.815Hz, reduced 0.185Hz, with controlling, target 0.1883Hz is quite approaching, and the voltage drop low value of three phase electrolytic aluminium loads is as shown in table 1 with the control desired value.

Table 1 each phase electrolytic aluminium load busbar voltage reduction value and the contrast of control desired value

Electrolytic aluminium factory	The first phase electrolytic aluminium factory	The second phase electrolytic aluminium factory	Three phase electrolytic aluminium factories
				Control desired value	0.0685p.u.	0.0681p.u.	0.06745p.u.
Actual reduction value	0.0680p.u.	0.0700p.u.	0.0654p.u.
				Error	-0.0005p.u.	0.0019p.u.	-0.00205p.u.

By table 1 analysis, can draw, control desired value and the actual reduction value of the load busbar voltage of each phase electrolytic aluminium load are quite approaching, maximum departure is 0.00205p.u., and under lower surface analysis, control desired value and the actual reduction value of each phase electrolytic aluminium load, as shown in table 2.

The load reduction value of each phase electrolytic aluminium load of table 2 and the contrast of control desired value

Electrolytic aluminium factory	The first phase electrolytic aluminium factory	The second phase electrolytic aluminium factory	Three phase electrolytic aluminium factories
				Control desired value	39.1727MW	49.856MW	75.971MW
Actual reduction value	38.2353MW	50.714MW	71.579MW
				Error	-0.9374MW	0.858MW	-4.392MW

Analyze and can draw by table 2, target load reduction value and the actual reduction value of each phase electrolytic aluminium load are very approaching, and maximum departure is only the 4.392MW of three phase electrolytic aluminiums loads, with respect to the three phase electrolytic aluminium load error of 640MW, seem very little.

Each fired power generating unit set end voltage reduction value of table 3 and the contrast of control desired value

By his-and-hers watches 3 comparative analyses, draw, take after the novel closed loop control method of this paper control desired value and the actual reduction value of each fired power generating unit set end voltage very approaching, maximum error is that No. 1 and No. 2 fired power generating unit are only 0.0053p.u., the 0.0002p.u. that the error of minimum is No. 3 fired power generating unit.

Simulation results show the validity of closed-loop control system gain parameter acquisition methods of the pull-in frequency FEEDBACK CONTROL voltage analyzed based on voltage sensibility and the validity that pull-in frequency deviation FEEDBACK CONTROL voltage is realized the meritorious closed loop control method of regulating, ask for the gain parameter of each frequency departure feedback by the voltage sensibility analytical method, the pull-in frequency deviation realizes closed-loop control to excitation system, has effectively controlled the stability of island network after the accident.

Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various modifications or supplement or adopt similar mode to substitute described specific embodiment, but can't depart from spirit of the present invention or surmount the defined scope of appended claims.

Claims (5)

1. a pull-in frequency deviation FEEDBACK CONTROL voltage is realized the meritorious closed loop control method of regulating, and it is characterized in that comprising the following steps:

The stand-by heat amount of capacity of step 1, the power disturbance size of utilizing the WAMS real-time monitoring system to be subject to and system, obtain thereby calculate the two difference the imbalance power Δ P that system exists, and the computing formula of described imbalance power Δ P is:

ΔP=P _step-P _reserve

Wherein, Δ P means the imbalance power of system, P _stepfor the power disturbance value that system is subject to, P _reservespinning reserve for system;

Step 2, according to the ratio of the capacity of aluminium manufacturer load, the system imbalance power Δ P measured is carried out to reasonable distribution, concrete grammar is: the definition island network has i load point, calculating this i load point according to this allocation rule needs respectively the load reduced, and then utilizes the model parameter of the rectification load that IEEE load modeling working group recommends to calculate the voltage adjustment amount of the busbar voltage of each load point;

Step 3, utilize the method for voltage sensibility analysis to ask for voltage sensibility matrix and the electrical distance matrix of system, thereby draw the relation between load bus voltage variety and power generator electrode terminal voltage variable quantity; The busbar voltage reduction value of each load bus of then obtaining in integrating step 2, obtain out the voltage adjustment amount of the set end voltage of each fired power generating unit;

Step 4, utilize the unit power regulation of the remaining meritorious pondage of fired power generating unit and fired power generating unit to calculate the frequency departure of system, then utilize the voltage adjustment amount of each fired power generating unit set end voltage that step 3 calculates to calculate the gain parameter of the frequency departure feedback element of each fired power generating unit excitation system;

Step 5, utilize the gain parameter value of the frequency departure feedback element of determined each fired power generating unit excitation system of step 4, the input using the frequency departure feedback as excitation system excitation reference voltage link, realized that frequency-voltage coordinates to control.

2. a kind of pull-in frequency deviation FEEDBACK CONTROL voltage according to claim 1 is realized the meritorious closed loop control method of regulating, and it is characterized in that, in described step 2, the Mathematical Modeling of the rectification load that IEEE load modeling working group is recommended is based on following formula:

wherein, P _n, U _n, f _nbe respectively rated power, voltage, the frequency of rectification load bus, P, U, f are respectively actual power, voltage, the frequency of rectification load bus;

The voltage adjustment amount computing formula of the busbar voltage of each load point is as follows:

Wherein, Δ U _lithe voltage adjustment amount that means i rectification load, U _before, U _afterthe voltage of i rectification load before and after meaning respectively to adjust, P _before, P _afterthe power of i rectification load before and after meaning respectively to adjust, mean the voltage that i rectification loaded.

3. a kind of pull-in frequency deviation FEEDBACK CONTROL voltage according to claim 1 is realized the meritorious closed loop control method of regulating, it is characterized in that, the concrete methods of realizing of described step 3 is: the voltage sensibility matrix and the electrical distance matrix that at first calculate system, then utilize the electrical distance matrix calculated to find out the nearest load bus of each fired power generating unit electrical distance, the voltage adjustment amount that the load bus that finally utilization calculates and the voltage sensibility between the generator node calculate the generator node.

4. a kind of pull-in frequency deviation FEEDBACK CONTROL voltage according to claim 1 is realized the meritorious closed loop control method of regulating, it is characterized in that, in described step 4, in the situation that system imbalance power and difference coefficient are known, can calculate the frequency departure of system, computing formula is as follows:

${\mathrm{\&Delta;P}}_G=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&Delta;P}}_{\mathrm{Gi}}=-\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{K}_{\mathrm{Gi}}\&CenterDot;\mathrm{\&Delta;f}=-\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\frac{1}{{\mathrm{\&sigma;}}_{i*}}\&CenterDot;\frac{P_{\mathrm{GiN}}}{f_N}\&CenterDot;\mathrm{\&Delta;f}$

Wherein, Δ P _gthe reserve capacity that means the island network system, K _githe power of each fired power generating unit-frequency static characteristic coefficient in expression island network system, also referred to as unit power regulation, σ _i*the difference coefficient that means each fired power generating unit in the island network system, P _giNspecified active power for each fired power generating unit;

The frequency departure that utilization calculates and set end voltage adjustment amount can calculate the gain parameter of the frequency departure feedback element of each fired power generating unit excitation system, and computing formula is as follows:

K _i·Δf=ΔU _Gi

Wherein, the frequency departure that Δ f is system, Δ U _gibe the set end voltage adjustment amount of i platform fired power generating unit, K _iit is the frequency departure feedback oscillator parameter of i platform fired power generating unit.

5. a kind of pull-in frequency deviation FEEDBACK CONTROL voltage according to claim 1 is realized the meritorious closed loop control method of regulating, it is characterized in that, in described step 5, realized that the concrete grammar that frequency-voltage is coordinated to control is: utilize the acquisition system frequency of PMU real-time high-precision, using frequency departure amount Δ f as field regulator reference voltage V _refpositive feedback, realize frequency-voltage real-time closed-loop control, when system emergent power vacancy causes frequency to descend, frequency deviation f can reduce the set end voltage reference value in field regulator, thereby reduce the output of field regulator, reduce the idle output of generator, to the load bus voltage drop, load power reduces, until system reaches new balance point.

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