A new method in calculating line sensitivities for power system equivalencing

Shultz, Richard D.; Muslu, Mesut; Smith, Robert

doi:10.1109/59.336116

Cited by 11 publications

(4 citation statements)

References 7 publications

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“…Limited by the computing power of computers and the computing scale of simulation software, it will become more and more difficult to directly build the entire power system in simulation software and perform simulation calculations. Therefore, in actual engineering calculations, only the detailed modeling of the research area is needed, while the rest of the grid can be simplified equivalently [2,3]. However, in the context of the electricity market, each power company in China belongs to different interests that are both cooperating and competing with each other.…”

Section: Introductionmentioning

confidence: 99%

Static Equivalence Method of Power Grid Based on Genetic Algorithm

Jiang,

Pan,

Wang

et al. 2024

Electronics

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When the electromagnetic transient simulation of a large-scale power grid is carried out, because the simulation is limited by the scale of simulation software, it is necessary to divide the grid into internal and external grids, and the external grid is modeled with equivalent simplification. Aiming at resolving the difficulties of the traditional grid equivalence method, such as a cumbersome calculation process and harsh calculation conditions, a static grid equivalence method based on the genetic algorithm is proposed in this paper. The method first constructs an external grid equivalence network, which includes coupling branches between boundary nodes, and each boundary node is connected to the external grid equivalence power supply through the branches. Then, the external grid equivalence model is used to establish an optimization model for solving the equivalence network parameters based on the information of the internal network, the difference of the power input from the external grid to the boundary nodes before and after equivalence is used as the objective function, and the genetic algorithm is used to realize the iterative optimization of the objective function to obtain a set of optimal post-equivalence network model parameters so that the state variables of the internal power grid before and after the equivalence are matched. The accuracy and effectiveness of the proposed method are verified through simulation with the CERPI36V7 node system.

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Section: Introductionmentioning

confidence: 99%

Static Equivalence Method of Power Grid Based on Genetic Algorithm

Jiang,

Pan,

Wang

et al. 2024

Electronics

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“…1) Topological equivalence of known external network information. Thevenin, Norton equivalent method, Ward equivalent method, REI equivalent method and their variants can be adopted at this case [6][7][8][9][10][11][12], which are relatively mature. However, the common defect of this kind of methods is how to maintain the accuracy in different situation, especial while the internal network experiencing a great change from the original.…”

Section: Introductionmentioning

confidence: 99%

Online Equivalent Method of External Network Based on Measurement Information

Xiao¹,

Gan²,

Lin³

et al. 2020

dtetr

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How to acquire the accurate equivalent network of external system in the interconnected power grid has always been a challenging issue in the fields of both academic and engineering. This paper proposes a new method for online equivalence of the external network based on the measurement information of the internal network. Firstly, it builds an equivalent network of the external system, including the coupled branches between each of the boundary node, the equivalent generators and the equivalent lines from corresponding boundary nodes to them. Then, based on the SCADA (Supervisory Control and Data Acquisition) measurement information, an optimization model to estimate the parameters of the equivalent network is constructed, with the minimization of the mismatch between the boundary's measurement and the calculation value of the equivalent network being the objective and the parameters of each line of the equivalent network within the reasonable range being the constraints. In order to reduce the calculation scale, measure is adopted to remove the coupled lines whose electrical distances (or impedances) are larger than a relative big threshold. The impedance range of each line in the equivalent network is determined by ward equivalent method under the condition of maximum and minimum operation mode. The model is solved by interior point method, which owns the satisfactory convergency performance. The solution of the model makes each of the calculated value of the equivalent network at the boundary node closest to the measured value, while all the parameters of the equivalent network within a practical range. The results of an example demonstrate the validity and effectiveness of the model and method proposed in the paper.

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“…This type of equivalent method is called as topological method. The main methods include Ward equivalent [3], [4], extended Ward equivalent [5], [6], sensitivity equivalent [7]- [9] and so on. Amongst them, the general Ward equivalent circuit model consists of the admittance between boundary nodes, grounding impedance and power injection which are connected to boundary nodes.…”

Section: Introductionmentioning

confidence: 99%

A Black-Box External Equivalent Method Using Tie-Line Power Mutation

et al. 2019

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A new black-box equivalent method by using tie-line power mutation is proposed in this paper, which is especially suitable for a two-port or three-port interconnected grid that does not know any information of the external network. The proposed method, based on the simplified Ward equivalent model of the external network, aims to addresses the following issues: unstable parameter estimation of the existing black-box-based static equivalence method and low accuracy or difficult implementation. Correspondingly, the main features of the proposed method, which makes it as a solution for these existing issues above, are summarized as follows: 1) it is easy to implement, as it only involves the associated measurements of boundary nodes in two adjacent time instants that are before and after a designed large disturbance of the internal grid; 2) it is robust to measurement errors, thus guaranteeing more accurate equivalent modeling; and 3) it can be applied to both the two-port and three-port equivalent networks. The simulation results of the New England 39-node test case and the actual electric grid case in Guangdong of China validate the effectiveness and performance of the proposed method. INDEX TERMS Static equivalent method, black-box external network, parameter estimation, tie line, power mutation.

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A new method in calculating line sensitivities for power system equivalencing

Cited by 11 publications

References 7 publications

Static Equivalence Method of Power Grid Based on Genetic Algorithm

Static Equivalence Method of Power Grid Based on Genetic Algorithm

Online Equivalent Method of External Network Based on Measurement Information

A Black-Box External Equivalent Method Using Tie-Line Power Mutation

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