CN106887852A - A kind of batch (-type) distributed power source voltage ＆ var control strategy setting method on the spot - Google Patents

Abstract

A setting method of local voltage and reactive power control strategy for intermittent distributed power sources: According to the selected power distribution system, input line parameters, load levels, network topology connection relationship, system operating voltage constraints and branch current limits, intermittent distribution The type, access location, capacity and parameters of the distributed power supply, the load and intermittent distributed power supply operating characteristic prediction curve in the operation optimization period, the initial value of the system reference voltage and reference power; establish the intermittent distributed power supply of the active distribution network On-site voltage and reactive power control strategy tuning model; linearize the nonlinear objective function and constraints in the model to make it a mixed integer linear programming model; solve the mixed integer linear programming model with a mixed integer linear programming solution tool; Output the solution result. The invention fully considers the randomness and volatility of distributed power sources and loads, uses a mixed integer linear programming method to solve the problem, and obtains an intermittent distributed power source local voltage and reactive power control strategy.

Description

A local voltage and reactive power control strategy setting method for intermittent distributed power generation

technical field

The invention relates to a local control strategy of a distributed power supply. In particular, it relates to an intermittent distributed power generation local voltage and reactive power control strategy setting method.

Background technique

The high attention to energy and the environment makes the development of distribution networks face new pressures and challenges, and these pressures and challenges are also important opportunities to promote the development of traditional distribution networks to active distribution networks. In recent years, a large number of intermittent distributed generation (Distributed Generation, DG) including photovoltaic (Photovoltaic, PV) and wind turbines have been connected to the distribution network. As the penetration rate of intermittent distributed power continues to increase, problems such as reverse power flow, reactive power and voltage control are becoming more and more serious. In particular, the access of intermittent distributed power generation has strong uncertainty in both time and space, which often leads to large fluctuations in feeder power during operation, resulting in serious voltage limit problems.

At present, the active distribution network mainly adopts two different strategies of centralized control and local control to realize the operation control of the system. Among them, the centralized control strategy can use global information, uniformly deploy controllable resources, and obtain globally optimized control performance. However, with the increase in the penetration rate of intermittent distributed power in active distribution networks, large-scale intermittent distributed The massive amount of data brings a heavy burden of communication and data processing, the delay of the centralized control strategy increases, and when the central control system fails, the entire system has the risk of failure; in addition, due to privacy and security concerns Consider that centralized control may not be able to capture detailed information. Although local control can only obtain local measurement information and cannot achieve global optimality, it does not require information exchange or remote measurement between nodes, thereby reducing the amount of communication data and the dimension of control variables; at the same time, due to the distributed The fluctuation of conventional power generation is large, and the local control strategy can respond quickly, so as to quickly suppress the fluctuation.

Since the power regulation of intermittent distributed power is continuously changing, its operation optimization problem is expanded from a single time section to a continuous time series, and the local voltage reactive power of intermittent distributed power in the active distribution network must be time-series The control strategy tuning model is used as the basis for solving the optimization problem. The mathematics of this model is essentially a mixed integer nonlinear programming problem, which brings great challenges to the calculation and solution. Therefore, there is a need for a linearization method that can transform the mixed integer nonlinear programming problem into a mixed integer linear programming problem that can be solved efficiently, so as to solve the local voltage and reactive power control strategy tuning of intermittent distributed power generation in active distribution network Model, so as to formulate the local voltage and reactive power control strategy of intermittent distributed power generation.

Contents of the invention

The technical problem to be solved by the present invention is to provide an intermittent distributed power source local voltage and reactive power control strategy setting method that fully considers the randomness and fluctuation of distributed power source and load.

The technical solution adopted in the present invention is: a method for setting the local voltage and reactive power control strategy of an intermittent distributed power supply, comprising the following steps:

1) According to the selected power distribution system, input line parameters, load level, network topology connection relationship, system operating voltage constraint and branch current limit, type of intermittent distributed power supply, access location, capacity and parameters, and optimize operation In-cycle load and intermittent distributed power supply operating characteristic prediction curve, initial value of system reference voltage and reference power;

2) According to the distribution system structure and parameters provided in step 1), considering the sequential characteristics of intermittent distributed power output and load, a local voltage and reactive power control strategy setting model for intermittent distributed power in active distribution networks is established, including : Select the root node as the balance node, set the minimum sum of voltage deviations of the active power distribution system as the objective function, and consider the system power flow constraints, system operation constraints, and intermittent distributed power supply operation constraints respectively;

3) Linearize the nonlinear objective function and constraint conditions in the local voltage and reactive power control strategy setting model of the intermittent distributed power generation in the active distribution network, and the transformed model in step 2) is a mixed integer linear programming model ;

4) Solving the mixed integer linear programming model using a mixed integer linear programming solution tool;

5) Output the solution result of step 4), that is, the relevant parameters of the intermittent distributed power supply voltage and reactive power control strategy.

The minimum sum of voltage deviations of the active distribution system described in step 2) is an objective function expressed as follows:

or

In the formula, N _T is the number of time sections, N _N is the total number of nodes in the system; V _t,i is the voltage amplitude of node i in period t; is the maximum voltage threshold, is the minimum voltage threshold, when V _t,i is not in the expected voltage range When , the objective function is used to reduce the voltage deviation.

The system power flow constraint described in step 2) is expressed as

In the formula, Ω _b is the set of branches; R _ji is the resistance of branch ji, X _ji is the reactance of branch ji; I _t,ji is the amplitude of the current flowing from node j to node i in period t; V _t,i is the voltage amplitude of node i in period t, V _t,j is the voltage amplitude of node j in period t; P _t,ij is the active power flowing from node i to node j in period t, Q _t,ij is the flow direction of node i in period t The reactive power of node j; P _t,ik is the active power flowing from node i to node k during t period, Q _t,ik is the reactive power flowing from node i to node k during t period; P _t,i is the The sum of the injected active power, is the active power injected by distributed power generation on node i in period t, is the active power consumed by the load on node i in period t, Q _t,i is the sum of reactive power injected on node i in period t, is the reactive power injected by distributed power generation on node i in period t, is the reactive power consumed by the load on node i in period t.

The system operating constraints described in step 2) are expressed as

In the formula, V ^max is the maximum value allowed by the system voltage, V ^min is the minimum value allowed by the system voltage; I ^max is the maximum value allowed by the branch current, V _t,i is the voltage amplitude of node i during the t period, I _{t , ij} is the magnitude of the current flowing from node i to node j in period t.

Step 2) The intermittent distributed power generation operation constraint is expressed as

In the formula, is the intermittent distributed power supply capacity of node i, is the upper limit of reactive power that the intermittent distributed power supply on node i can provide in period t; is the active power injected by intermittent distributed power generation on node i during t period, is the reactive power injected by intermittent distributed power generation on node i in period t; V _t,i is the voltage amplitude of node i in period t, is the expression of the local voltage and reactive power control strategy of intermittent distributed power generation, There is a regulation dead zone with are the minimum and maximum values of the voltage regulation dead zone of the local voltage and reactive power control strategy, respectively. In the dead zone, the reactive power generated by the intermittent distributed power supply is 0Var; the following formula constitutes the local voltage of the intermittent distributed power supply Expression of reactive power control strategy

Step 3) includes:

(1) Use U _{t,i to} replace the quadratic term Linearize the system power flow constraints and system operating constraints:

(V ^min ) ² ＝U _2,t,i ≤(V ^max ) ² (15)

In the formula, R _ij is the resistance of branch ij, _Xij is the reactance of branch ij; I _t,ij is the current amplitude of node i flowing to node j in t period; V _t,i is the voltage amplitude of node i in t period P _t,ij is the active power flowing from node i to node j in period t, Q _t,ij is the reactive power flowing from node i to node j in period t; V ^max is the maximum value allowed by the system voltage, and V ^min is the system voltage the minimum value allowed;

(2) The objective function contains an absolute value term Replace with auxiliary variable A _t,i and add constraints:

At _t,i ≥ 0 (19)

In the formula, N _T is the number of time sections, N _N is the total number of system nodes; is the maximum voltage threshold, is the minimum voltage threshold;

(3) Expression of local voltage and reactive power control strategy for intermittent distributed power generation is a nonlinear expression, using piecewise linearization to realize the Exact linearization of ; by introducing auxiliary variables a _t,i,n ,n=1,2,…,6 and d _t,i,n ,n=1,2,…,5, approximated by a series of line segments The defined curves are as follows:

a _t,i,1 ≤d _t,i,1 ,a _t,i,6 ≤d _t,i,5 (22)

a _t,i,n ≤d _t,i,n +d _t,i,n-1 ,n=2,3,4,5 (23)

a _t,i,n ≥0,d _t,i,n ∈{0,1} (24)

In the formula, a _t,i,n ,n=1,2,...,6 are continuous variables, d _t,i,n ,n=1,2,...,5 are integer variables; with are the minimum and maximum values of the voltage regulation dead zone of the local voltage and reactive power control strategy;

Introduce auxiliary integer variables c _i,1 and c _i,2 to convert the non-linear product term with Linearization is expressed as:

c _i,1 ≤ c i _,2 (28)

Among them, a _t,i,3 c _i,1 and a _t,u,4 c _i,2 are nonlinear product terms, and binary variables l _i,1,m and l _i,2,m are introduced, m=0,1 ,…,4, represent a _t,i,3 c _i,1 and a _t,i,4 c _i,2 respectively:

Introduce auxiliary variable w _{t,i,1,m to} replace a _t,i,3 l _i,1,m , auxiliary variable w _{t,i,2,m to} replace a _t,i,4 l _i,2,m , and Add the following constraints, where M is a sufficiently large positive real number:

a _t,i,3 -(1-l _i,1,m )M≤w _t,i,1,m ≤a t, _i,3 (31)

0≤w _t,i,1,m ≤l _i,1,m M (32)

a _t,i,4 -(1-l _i,2,m )M≤w _t,i,2,m ≤a t, _i,4 (33)

0≤w _t,i,2,m ≤l _i,2,m M (34)

(4) The system power flow constraints and system operation constraints contain place it at the predicted value point Perform first-order Taylor expansion and add constraints:

h _t,ij ≤(I ^max ) ² (38)

In the formula, Ω _b is the set of branches; P _t,ji is the active power flowing from node j to node i during t period, Q _t,ji is the reactive power flowing from node j to node i during t period; R _ji is the branch ji X _ji is the reactance of branch ji; P _t,i is the sum of active power injected on node i during t period, Q _t,i is the sum of reactive power injected on node i during t period; P _t, i _ik is the active power flowing from node i to node k in period t, Q _t,ik is the reactive power flowing from node i to node k in period t; I ^max is the maximum allowable branch current.

A method for setting the local voltage and reactive power control strategy of intermittent distributed power sources of the present invention is based on solving the problem of setting the local voltage and reactive power control strategies of intermittent distributed power sources under continuous time series, fully considering distributed power sources and Considering the randomness and fluctuation of the load, the local voltage and reactive power control strategy setting model of the intermittent distributed power generation in the active distribution network is established, and the mixed integer linear programming method is used to solve the problem, and the local voltage and reactive power control of the intermittent distributed power generation is obtained. Strategy.

Description of drawings

Figure 1 is the structure diagram of the revised IEEE 69 node calculation example;

Fig. 2 is a flow chart of a method for setting an intermittent distributed power supply local voltage and reactive power control strategy of the present invention;

Figure 3 is the prediction curve of intermittent distributed power supply and load operation characteristics;

Fig. 4a is the local voltage and reactive power control strategy of the intermittent distributed power at node 26 obtained after optimization;

Figure 4b shows the local voltage and reactive power control strategy of the intermittent distributed power at node 50 obtained after optimization;

Figure 5 is the reactive power compensation situation issued by intermittent distributed power;

Fig. 6 a is the voltage distribution situation at node 26 before and after optimization;

Fig. 6 b is the voltage distribution at node 50 before and after optimization;

Figure 7 shows the distribution of the extreme voltage of the whole network under different control strategies.

detailed description

In the following, a method for setting a local voltage and reactive power control strategy of an intermittent distributed power supply according to the present invention will be described in detail in combination with the embodiments and the accompanying drawings.

As shown in Figure 2, a method for setting an intermittent distributed power supply local voltage and reactive power control strategy of the present invention includes the following steps:

1) According to the selected power distribution system, input line parameters, load level, network topology connection relationship, system operating voltage constraint and branch current limit, type of intermittent distributed power supply, access location, capacity and parameters, and optimize operation In-cycle load and intermittent distributed power supply operating characteristic prediction curve (as shown in Figure 3), the initial value of the system reference voltage and reference power;

2) According to the distribution system structure and parameters provided in step 1), considering the sequential characteristics of intermittent distributed power output and load, a local voltage and reactive power control strategy setting model for intermittent distributed power in active distribution networks is established, including : Select the root node as the balance node, set the minimum sum of voltage deviations of the active distribution system as the objective function, and consider the system power flow constraints, system operation constraints, and intermittent distributed power supply operation constraints respectively; where

(1) The minimum sum of voltage deviations of the active power distribution system is the objective function expressed as follows:

or

In the formula, N _T is the number of time sections, N _N is the total number of nodes in the system; V _t,i is the voltage amplitude of node i in period t; is the maximum voltage threshold, is the minimum voltage threshold, when V _t,i is not in the expected voltage range When , the objective function is used to reduce the voltage deviation.

(2) The system power flow constraints described in (2) are expressed as

In the formula, Ω _b is the set of branches; R _ji is the resistance of branch ji, X _ji is the reactance of branch ji; I _t,ji is the amplitude of the current flowing from node j to node i in period t; V _t,i is the voltage amplitude of node i in period t, V _t,j is the voltage amplitude of node j in period t; P _t,ij is the active power flowing from node i to node j in period t, Q _t,ij is the flow direction of node i in period t The reactive power of node j; P _t,ik is the active power flowing from node i to node k during t period, Q _t,ik is the reactive power flowing from node i to node k during t period; P _t,i is the The sum of the injected active power, is the active power injected by distributed power generation on node i in period t, is the active power consumed by the load on node i in period t, Q _t,i is the sum of reactive power injected on node i in period t, is the reactive power injected by distributed power generation on node i in period t, is the reactive power consumed by the load on node i in period t.

(3) The system operation constraints described in (3) are expressed as

In the formula, V ^max is the maximum value allowed by the system voltage, V ^min is the minimum value allowed by the system voltage; I ^max is the maximum value allowed by the branch current, V _t,i is the voltage amplitude of node i during the t period, I _{t , ij} is the magnitude of the current flowing from node i to node j in period t.

(4) The intermittent distributed power generation operation constraint is expressed as

In the formula, is the intermittent distributed power supply capacity of node i, is the upper limit of reactive power that the intermittent distributed power supply on node i can provide in period t; is the active power injected by intermittent distributed power generation on node i during t period, is the reactive power injected by intermittent distributed power generation on node i in period t; V _t,i is the voltage amplitude of node i in period t, is the expression of the local voltage and reactive power control strategy of intermittent distributed power generation, There is a regulation dead zone with are the minimum and maximum values of the voltage regulation dead zone of the local voltage and reactive power control strategy, respectively. In the dead zone, the reactive power generated by the intermittent distributed power supply is 0Var; the following formula constitutes the local voltage of the intermittent distributed power supply Expression of reactive power control strategy

3) Linearize the nonlinear objective function and constraint conditions in the local voltage and reactive power control strategy setting model of the intermittent distributed power generation in the active distribution network, and the transformed model in step 2) is a mixed integer linear programming model ;include:

(1) Use U _{t,i to} replace the quadratic term Linearize the system power flow constraints and system operating constraints:

(V ^min ) ² ≤U _2,t,i ≤(V ^max ) ² (15)

In the formula, R _ij is the resistance of branch ij, _Xij is the reactance of branch ij; I _t,ij is the current amplitude of node i flowing to node j in t period; V _t,i is the voltage amplitude of node i in t period P _t,ij is the active power flowing from node i to node j in period t, Q _t,ij is the reactive power flowing from node i to node j in period t; V ^max is the maximum value allowed by the system voltage, and V ^min is the system voltage The minimum value allowed.

(2) The objective function contains an absolute value term Replace with auxiliary variable A _t,i and add constraints:

At _t,i ≥ 0 (19)

In the formula, N _T is the number of time sections, N _N is the total number of system nodes; is the maximum voltage threshold, is the minimum voltage threshold.

(3) Expression of local voltage and reactive power control strategy for intermittent distributed power generation is a nonlinear expression, using piecewise linearization to realize the Exact linearization of ; by introducing auxiliary variables a _t,i,n ,n=1,2,…,6 and d _t,i,n ,n=1,2,…,5, approximated by a series of line segments The defined curves are as follows:

a _t,i,1 ≤d _t,i,1 ,a _t,i,6 ≤d _t,i,5 (22)

a _t,i,n ≤d _t,i,n +d _t,i,n-1 ,n=2,3,4,5 (23)

a _t,i,n ≥0,d _t,i,n ∈{0,1} (24)

In the formula, a _t,i,n ,n=1,2,...,6 are continuous variables, d _t,i,n ,n=1,2,,5 are integer variables; with are the minimum and maximum values of the voltage regulation dead zone of the local voltage and reactive power control strategy;

Introduce auxiliary integer variables c _i,1 and c _i,2 to convert the non-linear product term with Linearization is expressed as:

c _i,1 ≤ c i _,2 (28)

Among them, a _t,i,3 c _i,1 and a _t,i,4 c _i,2 are non-linear product terms, introduce binary variables l _i,1,m and l _i,2,m , m=0,1 ,…,4, represent a _t,i,3 c _i,1 and a _t,i,4 c _i,2 respectively:

Introduce auxiliary variable w _{t,i,1,m to} replace a _t,i,3 l _i,1,m , auxiliary variable w _{t,i,2,m to} replace a _t,i,4 l _i,2,m , and Add the following constraints, where M is a sufficiently large positive real number:

a _t,i,3 -(1-l _i,1,m )M≤w _t,i,1,m ≤a t, _i,3 (31)

0≤w _t,i,1,m ≤l _i,1,m M (32)

a _t,i,4 -(1-l _i,2,m )M≤w _t,i,2,m ≤a t, _i,4 (33)

0≤w _t,i,2,m ≤l _i,2,m M (34)

(4) The system power flow constraints and system operation constraints contain place it at the predicted value point Perform first-order Taylor expansion and add constraints:

In the formula, Ω _b is the set of branches; P _t,ji is the active power flowing from node j to node i during t period, Q _t,ji is the reactive power flowing from node j to node i during t period; R _ji is the branch ji X _ji is the reactance of branch ji; P _t,i is the sum of active power injected on node i during t period, Q _t,i is the sum of reactive power injected on node i during t period; P _t, i _ik is the active power flowing from node i to node k in period t, Q _t,ik is the reactive power flowing from node i to node k in period t; I ^max is the maximum allowable branch current.

4) Solving the mixed integer linear programming model using a mixed integer linear programming solution tool;

5) Output the solution result of step 4), that is, the relevant parameters of the intermittent distributed power supply voltage and reactive power control strategy.

The invention realizes the solution of the local voltage and reactive power control strategy setting method of the intermittent distributed power supply of the active distribution network based on the mixed integer linear programming method.

For the embodiment of the present invention, first input the impedance value of the line element in the IEEE 69 node system, the active power reference value and power factor of the load element, and the connection relationship of the network topology, the structure of the calculation example is shown in Figure 1, and the detailed parameters are shown in Table 1 and Table 2; node 26 is connected to a group of photovoltaic systems with a capacity of 2MVA; node 50 is connected to a group of wind turbines with a capacity of 2MVA; the upper and lower limits of safe operation of the voltage amplitude (per unit value) of each node are 1.10 and 0.90 respectively; Finally, set the reference voltage of the system to 12.66kV and the reference power to 1MVA. The expected operating range of node voltage is 0.95p.u.-1.05p.u.

The comparative analysis is carried out without using control means and on-site reactive power voltage control means. Scheme I does not use control means, and scheme II adopts the local voltage and reactive power control model. The simulation results are shown in Table 3.

The computer hardware environment for optimizing calculation is Intel(R) Xeon(R) CPU E5-1620, the main frequency is 3.70GHz, and the memory is 8GB; the software environment is Windows 7 operating system.

The relevant parameters of the local voltage and reactive power control strategy of the intermittent distributed power generation can be optimized by using the predicted data, as shown in Fig. 4a and Fig. 4b. The amount of reactive power compensation, as shown in Figure 5, can effectively reduce the voltage deviation. It can be seen from Fig. 6a, Fig. 6b and Fig. 7 that when no control means is used, the access of high-penetration distributed power will lead to severe voltage fluctuations. After the intermittent distributed power supply is used for on-site voltage reactive power adjustment, when the node voltage exceeds the limit, the intermittent distributed power supply absorbs reactive power; when the node voltage is low, the intermittent distributed power supply emits reactive power to reach the voltage The role of support, so that the system voltage is maintained at an ideal level. When the voltage is too high, the intermittent distributed power generation only absorbs reactive power to reduce the voltage level, as shown in Figure 4a, Figure 5 and Figure 6a.

Table 1 Load connection position and power of IEEE 69 node example

Table 2 IEEE 69 node calculation line parameters

Table 3 Comparison of simulation results under different control strategies

Control Strategy Voltage min/p.u. Maximum voltage/p.u. I. Not using control strategies 0.9298 1.0836 II. Local Control Strategies 0.9501 1.0794

Claims (6)

1. a kind of batch (-type) distributed power source voltage ＆ var control strategy setting method on the spot, it is characterised in that including following step Suddenly：

1) according to selected distribution system, incoming line parameter, load level, network topology annexation, system operation voltage Constraint and branch current limitation, the type of batch (-type) distributed power source, on-position, capacity and parameter, in the running optimizatin cycle The initial value of load and batch (-type) distributed power source operation characteristic prediction curve, system reference voltage and reference power；

2) according to step 1) the distribution system structure and parameter that provide, it is considered to the sequential that batch (-type) distributed power source is exerted oneself with load Characteristic, voltage ＆ var control strategy is adjusted model on the spot to set up active power distribution network batch (-type) distributed power source, including：Choose root section Point is balance nodes, sets the active minimum object function of power distribution system voltage deviation sum, consider respectively system load flow constraint, System operation constraint, the operation constraint of batch (-type) distributed power source；

3) by active power distribution network batch (-type) distributed power source, voltage ＆ var control strategy is adjusted Nonlinear Parameter letter in model on the spot Number and constraints carry out linearisation conversion, it is inverted after step 2) model be MILP model；

4) MILP model is solved into instrument using MILP to be solved；

5) export step 4) solving result, i.e. the relevant parameter of batch (-type) distributed power source voltage ＆ var control strategy.

2. batch (-type) distributed power source according to claim 1 voltage ＆ var control strategy setting method, its feature on the spot Be, step 2) described in the active minimum object function of power distribution system voltage deviation sum be expressed as follows：

Or

In formula, N_TFor when discontinuity surface number, N_NIt is system node sum；V_t,iIt is the voltage magnitude of t period node is；It is maximum Voltage threshold,It is minimum voltage threshold, works as V_t,iVoltage range is not being expectedWhen, object function is used for subtracting Small voltage deviation.

3. batch (-type) distributed power source according to claim 1 voltage ＆ var control strategy setting method, its feature on the spot Be, step 2) described in system load flow constraint representation be

${\mathrm{\Σ}}_{ji\∈{\mathrm{\Ω}}_b}(P_{t,ji}-R_{ji}{I}_{t,ji}^2)+P_{t,i}={\mathrm{\Σ}}_{ik\∈{\mathrm{\Ω}}_b}{P}_{t,ik}---\left(2\right)$

${\mathrm{\Σ}}_{ji\∈{\mathrm{\Ω}}_b}(Q_{t,ji}-X_{ji}{I}_{t,ji}^2)+Q_{t,i}={\mathrm{\Σ}}_{ik\∈{\mathrm{\Ω}}_b}{Q}_{t,ik}---\left(3\right)$

$V_{t,i}^2-V_{t,j}^2+(R_{ij}^2+X_{ij}^2)I_{t,ij}^2=2(R_{ij}{P}_{t,ij}+X_{ij}{Q}_{t,ij})---\left(4\right)$

$I_{t,ij}^2{V}_{t,i}^2=P_{t,ij}^2+Q_{t,ij}^2---\left(5\right)$

$P_{t,i}=P_{t,i}^{DG}-P_{t,i}^{LOAD}---\left(6\right)$

$Q_{t,i}=Q_{t,i}^{DG}-Q_{t,i}^{LOAD}---\left(7\right)$

In formula, Ω_bIt is the set of branch road；R_jiIt is the resistance of branch road ji, X_jiIt is the reactance of branch road ji；I_t,jiFor t period nodes j flows To the current amplitude of node i；V_t,iIt is the voltage magnitude of t period node is, V_t,jIt is the voltage magnitude of t period nodes j；P_t,ijIt is t Period node i flows to the active power of node j, Q_t,ijThe reactive power of node j is flowed to for t period node is；P_t,ikIt is the t periods Point i flows to the active power of node k, Q_t,ikThe reactive power of node k is flowed to for t period node is；P_t,iFor in t period node is The active power sum of injection,It is the active power of distributed power source injection in t period node is,It is the t periods The active power of load consumption, Q on point i_t,iIt is the reactive power sum injected in t period node is,It is t period node is The reactive power of upper distributed power source injection,It is the reactive power of load consumption in t period node is.

4. batch (-type) distributed power source according to claim 1 voltage ＆ var control strategy setting method, its feature on the spot Be, step 2) described in system operation constraint representation be

${\left(V^{min}\right)}^2\≤V_{t,i}^2\≤{\left(V^{max}\right)}^2---\left(8\right)$

$I_{t,ij}^2\≤{\left(I^{max}\right)}^2---\left(9\right)$

In formula, V^maxIt is the maximum that system voltage is allowed, V^minFor the minimum value that system voltage is allowed；I^maxFor branch current is permitted Perhaps maximum, V_t,iIt is the voltage magnitude of t period node is, I_t,ijThe current amplitude of node j is flowed to for t period node is.

5. batch (-type) distributed power source according to claim 1 voltage ＆ var control strategy setting method, its feature on the spot Be, step 2) described in batch (-type) distributed power source operation constraint representation be

$Q_{t,i}^{DG,max}=\sqrt{{\left(S_i^{DG}\right)}^2-{\left(P_{t,i}^{DG}\right)}^2}---\left(10\right)$

In formula,It is the batch (-type) distributed power source capacity of node i,It is batch (-type) distributed electrical in t period node is The available reactive power upper limit in source；It is the active power of batch (-type) distributed power source injection in t period node is,For The reactive power of batch (-type) distributed power source injection in t period node is；V_t,iIt is the voltage magnitude of t period node is,For The expression formula of batch (-type) distributed power source voltage ＆ var control strategy on the spot,In the presence of regulation dead band [V_i ^DG,min,V_i ^{DG ,max}], V_i ^DG,minAnd V_i ^DG,maxThe respectively minimum value and maximum in the voltage-regulation dead band of voltage ＆ var control strategy on the spot, In dead band, the reactive power that batch (-type) distributed power source is produced is 0Var；Following formula constitutes batch (-type) distributed power source with regard to ground voltage The expression formula of idle control strategy

6. batch (-type) distributed power source according to claim 1 voltage ＆ var control strategy setting method, its feature on the spot It is, step 3) include：

(1) U is used_t,iReplace quadratic termSystem load flow constraint and system operation are constrained into linearisation：

$U_{t,i}-U_{t,j}+(R_{ij}^2+X_{ij}^2)I_{t,ij}^2=2(R_{ij}{P}_{t,ij}+X_{ij}{Q}_{t,ij})---\left(13\right)$

$I_{t,ij}^2{U}_{t,i}=P_{t,ij}^2+Q_{t,ij}^2---\left(14\right)$

(V^min)²≤U_2,t,i≤(V^max)² (15)

In formula, R_ijIt is the resistance of branch road ij, X_ijIt is the reactance of branch road ij；I_t,ijThe electric current width of node j is flowed to for t period node is Value；V_t,iIt is the voltage magnitude of t period node is；P_t,ijThe active power of node j, Q are flowed to for t period node is_t,ijIt is the t periods Point i flows to the reactive power of node j；V^maxIt is the maximum that system voltage is allowed, V^minFor the minimum value that system voltage is allowed；

(2) absolute value term is contained in object functionUse auxiliary variable A_t,iReplace, and increase constraint：

$\min f={\mathrm{\Σ}}_{t=1}^{N_T}{\mathrm{\Σ}}_{i=1}^{N_N}{A}_{t,i}---\left(16\right)$

$A_{t,i}\≥U_{t,i}-{\left(V_{thr}^{\max }\right)}^2---\left(17\right)$

$A_{t,i}\≥-U_{t,i}+{\left(V_{thr}^{\min }\right)}^2---\left(18\right)$

A_t,i≥0 (19)

In formula, N_TFor when discontinuity surface number, N_NIt is system node sum；It is maximum voltage threshold,It is minimum voltage threshold Value；

(3) expression formula of batch (-type) distributed power source voltage ＆ var control strategy on the spotBe non-linear expressions, using point It is right that section linearisation is realizedExact linearization method；By introducing auxiliary variable a_t,i,n, n=1,2 ..., 6 and d_t,i,n, n=1, 2 ..., 5, using a series of line segments come approximateDefined curve, it is as follows：

$V_{t,i}=0.9a_{t,i,2}+a_{t,i,3}{V}_i^{DG,min}+a_{t,i,4}{V}_i^{DG,max}+1.1a_{t,i,5}+2a_{t,i,6}---\left(20\right)$

a_t,i,1≤d_t,i,1,a_t,i,6≤d_t,i,5 (22)

a_t,i,n≤d_t,i,n+d_t,i,n-1, n=2,3,4,5 (23)

a_t,i,n≥0,d_t,i,n∈{0,1} (24)

${\mathrm{\Σ}}_{n=1}^6{a}_{t,i,n}=1,{\mathrm{\Σ}}_{n=1}^5{d}_{t,i,n}=1---\left(25\right)$

In formula, a_t,i,n, n=1,2 ..., 6 is continuous variable, d_t,i,n, n=1,2 ..., 5 is integer variable；V_i ^DG,minAnd V_i ^DG,max The respectively minimum value and maximum in the voltage-regulation dead band of voltage ＆ var control strategy on the spot；

Introduce auxiliary integer variable c_i,1And c_i,2By non-linear product term a_t,i,3V_i ^DG,minAnd a_t,i,4V_i ^DG,maxLinearisation, then it represents that For：

a_t,i,3V_i ^DG,min=0.90a_t,i,3+0.01a_t,i,3c_i,1,0≤c_i,1≤20 (26)

a_t,i,4V_i ^DG,max=0.90a_t,i,4+0.01a_t,i,4c_i,2,0≤c_i,a≤20 (27)

c_i,1≤c_i,2 (28)

Wherein, a_t,i,3c_i,1And a_t,i,4c_i,2It is non-linear product term, introduces binary variable l_i,1,mAnd l_i,2,m, m=0,1 ..., 4, a is represented respectively_t,i,3c_i,1And a_t,i,4c_i,2：

$a_{t,i,3}{c}_{i,1}={\mathrm{\Σ}}_{m=0}^4{2}^m{a}_{t,i,3}{l}_{i,1,m}---\left(29\right)$

$a_{t,i,4}{c}_{i,2}={\mathrm{\Σ}}_{m=0}^4{2}^m{a}_{t,i,4}{l}_{i,2,m}---\left(30\right)$

Introduce auxiliary variable w_t,i,1,mReplace a_t,i,3l_i,1,m, auxiliary variable w_t,i,2,mReplace a_t,i,4l_i,2,m, and increase following constraint, It is sufficiently large arithmetic number wherein to take M：

a_t,i,3-(1-l_i,1,m)M≤w_t,i,1,m≤a_t,i,3 (31)

0≤w_t,i,1,m≤l_i,1,mM (32)

a_t,i,4-(1-l_i,2,m)M≤w_t,i,2,m≤a_t,i,4 (33)

0≤w_t,i,2,m≤l_i,2,mM (34)

(4) contain in system load flow constraint and system operation constraintBy it in predicted value pointCarry out First order Taylor launches, and increases constraint：

$h_{t,ij}\≈\[2P_{t,ij}{P}_{t,ij}^0+2Q_{t,ij}{Q}_{t,ij}^0-{\left(P_{t,ij}^0\right)}^2-{\left(Q_{t,ij}^0\right)}^2\]/{\left(V_{t,ij}^0\right)}^2---\left(35\right)$

${\mathrm{\Σ}}_{ji\∈{\mathrm{\Ω}}_b}(P_{t,ji}-R_{ji}{h}_{t,ij})+P_{t,i}={\mathrm{\Σ}}_{ik\∈{\mathrm{\Ω}}_b}{P}_{t,ik}---\left(36\right)$

${\mathrm{\Σ}}_{ji\∈{\mathrm{\Ω}}_b}(Q_{t,ji}-X_{ji}{h}_{t,ji})+Q_{t,i}={\mathrm{\Σ}}_{ik\∈{\mathrm{\Ω}}_b}{Q}_{t,ik}---\left(37\right)$

h_t,ij≤(I^max)² (38)

$U_{t,i}=U_{t,j}+2(R_{ij}{P}_{t,ij}+X_{ij}{Q}_{t,ij})-(R_{ij}^2+X_{ij}^2)h_{t,ij}---\left(39\right)$

In formula, Ω_bIt is the set of branch road；P_t,jiThe active power of node i, Q are flowed to for t period nodes j_t,jiIt is t period nodes j Flow to the reactive power of node i；R_jiIt is the resistance of branch road ji, X_jiIt is the reactance of branch road ji；P_t,iTo be injected in t period node is Active power sum, Q_t,iIt is the reactive power sum injected in t period node is；P_t,ikFor t period node is flow to node k Active power, Q_t,ikThe reactive power of node k is flowed to for t period node is；I^maxFor the maximum that branch current is allowed.