A Branch-Power-based State Estimation for Pseudo-Measured Loads in Distribution System

J.y. Wang and J.-q. Qu (PRC)


Load estimation, pseudo-measurement, distribution system, weight function


For the low redundancy of real-time measurement in distribution system, it requires adding the historical data and other relevant information as pseudo-measurement. Its low accuracy affects the result of estimation. To tackle the problem of low accuracy, a branch-power-based load estimation algorithm is proposed in this paper. It exploits the radial nature of distribution system and the linear relationship between equivalent measurement and the state variable. The actual measurements still use the conventional weighted least squares (WLS) method, accuracy as the weight; the pseudo-measurements use the weighted least absolute value (WLAV) method, weight changing with the error. It not only retains the merits of branch-power-based state estimation, but also restrains the bad data of the pseudo-measurement from affecting the result of estimation. The effectiveness and feasibility of the proposed algorithm is verified with numerical tests on PG&E 69-bus distribution system, and the computational speed is fast. It is prospective for online applications in distribution system.

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