CN106033896A - A method for automatic power generation control - Google Patents

Abstract

The invention discloses an automatic power generation control method. The automatic power generation control method comprises that: each power grid area j determines a current load variation quantity, a frequency deviation value of a power grid area i and a frequency deviation value of a power grid area k in each preset control cycle in the area, wherein the power grid area i is each area of the power grid area j that power flows to, and the power grid area k is each power grid area that the power of the power grid area j flows to; the power grid area j determines a power output control order and a control evaluation parameter of the local area in a current control cycle according to the load variation quantity and the frequency deviation value and according to a principle that a sum of system regulation expenditure and frequency deviation punishment is minimum; power generation control in a local area is performed according to the power output control order and frequency stability is obtained according to a control evaluation parameter. The automatic power generation control method can effectively realize stable frequency and low cost in the electric power system.

Description

A method for automatic power generation control

technical field

The invention relates to power system frequency control technology, in particular to an automatic generation control (AGC) method.

Background technique

In an interconnected power system, each regional grid maintains frequency stability within the system through automatic generation control (AGC). Generally speaking, frequency regulation will generate costs, so the regional power grid always wants to minimize its regulation costs, and generally requires optimal economic efficiency when performing automatic power generation control. Economic optimization is achieved when regions cooperate with each other.

The current automatic power generation control method adopts centralized control, that is, the control center collects real-time status information of each regional power grid, and performs unified decision-making control based on this. There are following problems in this method:

1. Due to the increase of uncertainty after wind power and other renewable energy sources are connected, the state information of each region changes rapidly. In this way, the state information mastered by the control center is easily outdated and inconsistent with the actual situation, which will reduce the Availability of centralized frequency control.

2. In practical applications, the number of regional power grids is huge, and the transmission and processing of a large amount of state information will also increase the resource overhead cost of centralized control, so it cannot meet the actual needs of minimizing the adjustment cost.

It can be seen that the existing automatic power generation control method has problems such as poor regulation performance and high regulation cost.

Contents of the invention

In view of this, the main purpose of the present invention is to provide an automatic power generation control method, which can effectively achieve frequency stability in the power system with low cost.

In order to achieve the above object, the technical scheme proposed by the present invention is:

An automatic power generation control method, comprising:

For each grid area j, in each preset control cycle, determine the current load variation in the area, the frequency deviation of the grid area i, and the frequency deviation of the grid area k, wherein the grid area i is the power flow To each grid area of the grid area j, the grid area k is each grid area to which the power of the grid area j flows;

The power grid area j, according to the load variation and the frequency deviation, and according to the principle that the sum of the system adjustment cost and the frequency deviation penalty is the smallest, determines the output control command and the control evaluation parameters of the current control period in this area and performing power generation control in the local area according to the output control instruction, and knowing the current frequency stability in the local area according to the control evaluation parameters.

To sum up, the automatic power generation control method proposed by the present invention adopts a distributed method, and each power grid area independently determines the output control command of the current control period in accordance with the principle of minimizing the sum of system adjustment expenses and frequency deviation penalties. In this way, frequency stability in the area can be ensured, and adjustment costs can be minimized.

Description of drawings

Fig. 1 is a schematic flow chart of Embodiment 1 of the present invention;

detailed description

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

The core idea of the present invention is: using a distributed control method, the main body of each area determines the corresponding control command for the area based on the sum of the adjustment cost and the frequency deviation penalty after the frequency deviation occurs. In this way, frequency stability in the area can be ensured, and adjustment costs can be minimized.

Since the interests of multiple stakeholders need to be considered here (that is, adjustment fees and frequency deviation penalties), the present invention will introduce game theory to make optimal decisions based on these related subjects.

Fig. 1 is a schematic flow chart of Embodiment 1 of the present invention, as shown in Fig. 1, this embodiment mainly comprises:

Step 101, for each grid area j, in each preset control period, determine the current load variation in the area, the frequency deviation of grid area i and the frequency deviation of grid area k, wherein the grid area i is each grid area where power flows to the grid area j, and grid area k is each grid area where the power of the grid area j flows.

In this step, each grid area will calculate the load variation of the area, the frequency deviation of the power inflow area and the frequency deviation of the power outflow area in each control cycle, so that these parameters can be used in the subsequent steps to determine The optimal output control command is obtained, and the specific methods for obtaining these parameters are within the grasp of those skilled in the art, and will not be repeated here.

It should be noted that, for a grid area, the frequency deviation of other grid areas connected to it can be obtained through physical measurement, and the frequency deviation of this area can be obtained through physical measurement or through the dynamic equations mentioned below.

The setting of the control cycle can be set by those skilled in the art according to actual needs, for example, it can be 1 minute.

Step 102, the power grid area j, according to the load change amount and the frequency deviation amount, and according to the principle that the sum of the system adjustment cost and the frequency deviation penalty is the smallest, determine the output control command of the area and the output control command of the area in the current control cycle. Control evaluation parameters; and perform power generation control in the local area according to the output control instruction, and obtain current frequency stability in the local area according to the control evaluation parameters.

In this step, by following the principle that the sum of system adjustment overhead and frequency deviation penalty is the smallest, determine the output control command in this area of the current control cycle, so as to ensure that the obtained output control command can meet: the frequency is stable and the control cost is the lowest. Require.

Preferably, the control evaluation parameters include: frequency deviation, power generation deviation, tie line power flowing from each power inflow area to its own area, and tie line power flowing from this area to each power outflow area.

Preferably, each power grid area can use the following method to determine the output control command and control evaluation parameters of the area in the current control period:

Computing Dynamic Equations $\left\{\begin{array}{c}{\stackrel{\&Center\; Dot;}{\mathrm{\ω}}}_j=-\frac{1}{m_j}({\mathrm{D.}}_j{\mathrm{\ω}}_j-P_j^m+P_j^L+\underset{k:j\&Right\; Arrow;k}{\mathrm{\Σ}}{P}_{\mathrm{jk}}-\underset{i:i\&Right\; Arrow;j}{\mathrm{\Σ}}{P}_{\mathrm{ij}})\\ {\stackrel{\·}{P}}_{\mathrm{ij}}=B_{\mathrm{ij}}({\mathrm{\ω}}_i-{\mathrm{\ω}}_j),i=1,...,V\\ {\stackrel{\&Center\; Dot;}{P}}_{\mathrm{jk}}=B_{\mathrm{jk}}({\mathrm{\ω}}_j-{\mathrm{\ω}}_k),k=1,...,W\\ {\stackrel{\&Center\; Dot;}{p}}_j^m=-(P_j^m-P_j^C+{\mathrm{\ω}}_j/R_j)/T_j\\ {\stackrel{\·}{P}}_j^C=-K_j{a}_j{\mathrm{\ω}}_j\end{array}\right.,$ The output control command and the control evaluation parameter are obtained.

Among them, ω _j is the frequency deviation of grid area j; M _j is the generator inertia coefficient of grid area j; D _j is the damping coefficient of grid area j; is the power generation deviation of grid area j; P jk is the load variation of grid area j; P _jk is the power of tie line flowing from grid area j to grid area k; is the sum of all tie-line powers flowing out of grid area j; P _ij is the tie-line power flowing from grid area i to grid area j; is the sum of all tie line power flowing to grid area j; B _ij is the reciprocal of the line reactance between grid area i and grid area j; ω _i is the frequency deviation of grid area i; B _jk is grid area j and The reciprocal of the line reactance between grid areas k; is the output control command of the grid area j; R _j is the response characteristic coefficient of the generator in the grid area j to the frequency deviation, which characterizes the response characteristic of the generator to the frequency deviation; K _j is the response characteristic of the control command of the grid area j to the frequency coefficient, which characterizes the response characteristics of the area control command to frequency; a _j is the frequency response coefficient of grid area j; i is the number of the grid area where power flows to grid area j; V is the total number of grid areas where power flows to the grid area j ; k is the number of the grid area where the power of grid area j flows; W is the total number of grid areas where the power of grid area j flows, Represents the derivative of the parameter x with respect to time.

Among the above parameters, M _j , D _j , B _ij , B _jk R _j , K _j and a _j are all known constants, and the specific acquisition methods are within the grasp of those skilled in the art, and will not be repeated here.

What needs to be explained here is that the above equations are based on game theory, with as the objective function, with $\left\{\begin{array}{c}{P}_j^m=P_j^L+{\mathrm{D.}}_j{\mathrm{\ω}}_j+\underset{k:j\&Right\; Arrow;k}{\mathrm{\Σ}}{P}_{\mathrm{jk}}-\underset{i:i\&Right\; Arrow;j}{\mathrm{\Σ}}{P}_{\mathrm{ij}}\\ P_j^m=P_j^L+\underset{k:j\&Right\; Arrow;k}{\mathrm{\Σ}}{P}_{\mathrm{jk}}-\underset{i:i\&Right\; Arrow;j}{\mathrm{\Σ}}{P}_{\mathrm{ij}}\end{array}\right.$ As a constraint condition, it is obtained by combining the dynamics of the power system and the dynamics of the control command, where, ${\stackrel{\&Center\; Dot;}{\mathrm{\ω}}}_j=-\frac{1}{m_j}({\mathrm{D.}}_j{\mathrm{\ω}}_j-P_j^m+P_j^L+\underset{k:j\&Right\; Arrow;k}{\mathrm{\Σ}}{P}_{\mathrm{jk}}-\underset{i:i\&Right\; Arrow;j}{\mathrm{\Σ}}{P}_{\mathrm{ij}})$ is the frequency response dynamic equation, is the tie-line power flow dynamic equation, the number of which is determined by the V, Reflecting the power outflow dynamic equation of the tie line, the number of equations is determined by the W, is the engine dynamic equation, The dynamic equations for the control instructions. In this way, it can be ensured that the obtained output control instruction and the value of the control evaluation parameter can meet the target And this goal is the goal of the minimum sum of system adjustment overhead and frequency deviation penalty. Therefore, it can be ensured that the frequency stability in the system can be achieved after control by the output control command obtained by solving the above equations, and the cost can be ensured. the lowest.

Specifically, the following methods can be used to know the current frequency stability in this area:

Comparing the control evaluation parameters obtained in this cycle with the corresponding parameters in the previous control cycle, if the change range is within the preset acceptable change range, then determine that the current local area is in a stable frequency state; otherwise, determine that the current local area In a state of frequency instability.

In the above method, the acceptable variation range of each control evaluation parameter can be set by those skilled in the art according to actual needs.

It can be seen from the above technical solution that the present invention determines the output control command in each control cycle based on the game theory and the principle that the sum of the system adjustment cost and the frequency deviation penalty is the smallest by adopting a distributed control method. It can not only ensure the frequency stability of the area, but also minimize the adjustment cost. In addition, the present invention can realize complete distributed control, does not require a centralized control center, and does not require a large amount of information interaction, so it can improve the flexibility of system operation and save costs.

Claims (4)

1. An automatic power generation control method, characterized in that, comprising: For each grid area j, in each preset control cycle, determine the current load variation in the area, the frequency deviation of the grid area i, and the frequency deviation of the grid area k, wherein the grid area i is the power flow To each grid area of the grid area j, the grid area k is each grid area to which the power of the grid area j flows; The power grid area j, according to the load variation and the frequency deviation, and according to the principle that the sum of the system adjustment cost and the frequency deviation penalty is the smallest, determines the output control command and the control evaluation parameters of the current control period in this area and performing power generation control in the local area according to the output control instruction, and knowing the current frequency stability in the local area according to the control evaluation parameters. 2. The method according to claim 1, wherein the control evaluation parameters include: frequency deviation, power generation deviation, tie-line power flowing from each power inflow area to this area, and power from this area to each Tie-line power in the power outflow area. 3. The method according to claim 2, wherein the determination of the output control command and control evaluation parameters in this area of the current control cycle comprises: Computing Dynamic Equations $\left\{\begin{array}{c}{\stackrel{\&Center\; Dot;}{\mathrm{\ω}}}_j=-\frac{1}{m_j}({\mathrm{D.}}_j{\mathrm{\ω}}_j-P_j^m+P_j^L+\underset{k:j\&Right\; Arrow;k}{\mathrm{\Σ}}{P}_{\mathrm{jk}}-\underset{i:i\&Right\; Arrow;j}{\mathrm{\Σ}}{P}_{\mathrm{ij}})\\ {\stackrel{.}{P}}_{\mathrm{ij}}=B_{\mathrm{ij}}({\mathrm{\ω}}_i-{\mathrm{\ω}}_j),i=1,..,V\\ {\stackrel{.}{P}}_{\mathrm{jk}}=B_{\mathrm{jk}}({\mathrm{\ω}}_j-{\mathrm{\ω}}_k),k=1,...,W\\ {\stackrel{.}{P}}_j^m=-(P_j^m-P_j^C+{\mathrm{\ω}}_j/R_j)/T_j\\ {\stackrel{.}{P}}_j^C=-K_j{a}_j{\mathrm{\ω}}_j\end{array}\right.,$ obtaining the output control instruction and the control evaluation parameter; Among them, ω _j is the frequency deviation of grid area j; M _j is the generator inertia coefficient of grid area j; D _j is the damping coefficient of grid area j; is the power generation deviation of grid area j; P jk is the load variation of grid area j; P _jk is the power of tie line flowing from grid area j to grid area k; is the sum of all tie-line powers flowing out of grid area j; P _ij is the tie-line power flowing from grid area i to grid area j; is the sum of all tie line power flowing to grid area j; B _ij is the reciprocal of the line reactance between grid area i and grid area j; ω _i is the frequency deviation of grid area i; B _jk is grid area j and The reciprocal of the line reactance between grid areas k; is the output control command of the grid area j; R _j is the response characteristic coefficient of the generator in the grid area j to the frequency deviation; K _j is the response characteristic coefficient of the control command of the grid area j to the frequency; a _j is the frequency of the grid area j Response coefficient; i is the grid area number where the power flows to the grid area j; V is the total number of grid areas where the power flows to the grid area j; k is the number of the grid area where the power of the grid area j flows; W is the grid area j The total number of grid areas where the power flows to, Represents the derivative of the parameter x with respect to time. 4. The method according to claim 1, wherein the acquiring the frequency stability of the current local area comprises: Comparing the control evaluation parameters obtained in this cycle with the corresponding parameters in the previous control cycle, if the change range is within the preset acceptable change range, then determine that the current local area is in a stable frequency state; otherwise, determine that the current local area In a state of frequency instability.