Voltage sag monitoring device configuration method considering dynamic network reconfiguration (DNR)

[0041] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0042] As the economic loss of production caused by voltage sag is becoming more and more serious, it is necessary to install voltage sag monitoring device. However, due to cost issues, it is not necessary to install voltage sag monitoring devices on all bus bars. Therefore, it is of engineering significance to study the optimal configuration of voltage sag monitoring devices. Existing research is carried out under a certain grid topology when optimizing the configuration of monitoring points. However, the actual situation is that the application of DNR will directly affect the changes in the network topology, resulting in changes in the impedance matrix of the grid, and the formula for short-circuit calculation needs to be changed accordingly, which may reduce the observability of voltage sags. The present invention is a method for configuring a voltage sag monitoring device considering the dynamic reconstruction of the network topology. Under the premise of ensuring the minimum number of monitoring devices installed, the power grid can meet the requirements of the entire network under the typical topology of any network topology dynamic reconstruction. The temporary drop is considerable, as follows:

[0043] 1. Get the historical typical topology of the power grid

[0044] The application of DNR will cause the grid topology to change with load changes. There are several typical topological structures corresponding to the typical load situation. After obtaining the historical switch data of the power grid, the historical typical topology of the power grid can be obtained. Generally, when there are N types of typical topologies in the power grid, it is recorded as the topology T 1 , Topology T 2 ,..., Topology T N.

[0045] 2. Preliminary configuration of monitoring device

[0046] For each historical typical topology of the power grid, the MRA method is used to initially configure the monitoring device. Corresponding to the historical typical topology of each power grid, a configuration method of monitoring devices that makes the entire network sag significantly is obtained (for a certain topology, there are generally multiple configuration methods to make the entire network sag significantly).

[0047] The method of using the MRA method to initially configure the monitoring device is as follows: Under each topology, a network impedance matrix is ​​formed according to the system parameters, and then fault points are set at equal intervals on each line of the entire network to obtain the entire network sag performance under any failure Observation area matrix M w :

[0048]

[0049] In the formula, n is the number of buses in the whole network, p is the number of fault points; w is the type of fault, and 0, 1, 2, and 3 represent three-phase, single-phase grounding, two-phase and two-phase grounding faults; M w It is a 0-1 binary matrix of order n×p. If the amplitude of the bus i when the w-type fault occurs at the j-th point is less than the threshold (the threshold is 0.9pu), take otherwise

[0050] M w The meaning of is: the element in the i-th row represents the MRA range of bus i, and the element value of 1 means that the fault point is within the MRA of bus i, otherwise it is outside the MRA of bus i.

[0051] The decision vector for installing the monitoring device is:

[0052] X=[x 1 x 2 … X n ]

[0053] Where x i =1 means that the monitoring device is installed on the bus i, x i =0 means no monitoring device is installed on bus i.

[0054] Take the minimum number of monitoring devices as the objective function:

[0055]

[0056] The sag caused by any failure can be monitored by at least one device as a constraint:

[0057]

[0058] In the formula, j = 1, 2,..., p; w = 0, 1, 2, 3; use the 0-1 programming algorithm to solve the planning problem.

[0059] When there are N typical topologies in the power grid, that is, topology T 1 , Topology T 2 ,..., Topology T N When, the algorithm will obtain the optimal configuration of the monitoring device as follows:

[0060]

[0061] Where R 1 , R 2 ,..., R N Corresponding to the historical typical topology T 1 , T 2 ,..., T N The configuration mode of all monitoring devices for the whole network is sag down considerably; r 1 , R 2 ,..., r N Represents the historical typical topology T 1 , T 2 ,..., T N , Respectively have r 1 , R 2 ,..., r N A configuration method of monitoring devices makes it meet the substantial sag of the whole network; X ab =[x ab(1) ,x ab(2) ,...,X ab(n) ] Means satisfying the historical typical topology T a The configuration mode of the b-th monitoring device for the whole network temporarily dropped, where a=1, 2,...,N; b=1,2,...,r a; N is the number of buses in the whole network; x ab(i) =1 means making the historical typical topology T of the power grid a The configuration of the b-th monitoring device with a considerable sag of the whole network decides to install the monitoring device on bus i, x ab(i) =0 means making the historical typical topology T of the power grid a The configuration of the b-th monitoring device, which has a considerable drop in the entire network, decides not to install the monitoring device on bus i.

[0062] Three, configuration synthesis

[0063] Comprehensively consider the configuration of monitoring devices obtained under each topology, and obtain a comprehensive way to ensure that the sag of the entire network under all typical topologies is considerable.

[0064] The method of selecting the comprehensive configuration is as follows:

[0065] First determine whether it exists Where d 1 1 to r 1 Any value between to, d 2 1 to r 2 Any value between to,..., d N 1 to r N Any value between to.

[0066] If it exists Ze Ling At this time, X is to ensure that the optimal configuration of monitoring devices for the entire network under each topology has a considerable sag. If it does not exist Suppose the decision vector for installing the monitoring device is:

[0067] X=[x 1 x 2 … X n ]

[0068] Where x i =1 means that the monitoring device is installed on the bus i, x i =0 means no monitoring device is installed on bus i.

[0069] Take the minimum number of monitoring devices as the objective function:

[0070]

[0071] To meet the constraints of the observability of the entire network under each topology:

[0072] Existence X ab Satisfy:

[0073]

[0074] In the formula, a=1,2,...,N; b=1,2,...,r a; K = 1, 2,..., n (n is the number of buses in the entire network). The 0-1 planning algorithm is used to solve the planning problem, and the optimal configuration of voltage sag monitoring devices can be obtained to ensure that the sag of the whole network is considerable and the number of monitoring devices is the least under all typical topologies.