Modeling of photovoltaic and wind turbine based distributed generation in state estimation

Abstract

This paper proposes an algorithm for distribution state estimation with included unmonitored (or partially monitored) photovoltaic generation and wind turbine&asynchronous generator based models, as well as distributed loads. These data are treated as pseudo measurements and included in the state estimation with lower weights. Initial state estimations for unmonitored (partially monitored) distributed generation and loads are calculated from the weather forecast data or daily load profiles, respectively. The pseudo measurements are additionally re-adjusted by the optimal load/generation reallocation procedure to fit the real-time measurements inside the weighted least square (WLS) based state estimation algorithm. The results and practical aspects of the proposed methodology are demonstrated on characteristic real-life urban distribution network with 40 buses.

Generalized State Estimation of Flexible AC Power Systems Considering Wind Generators and Primary Frequency Control

“…A PMU can provide a phasor measurement of the branch current of a WTG, a generator participating in the frequency regulation, and/or a voltage and frequency dependent load embedded at the kth node. Accordingly, the current equations at the terminals of one of these electric components are used for relating the measurement to the state variables, as given by (5), (6), and (7) for WTGs, generators participating in the frequency regulation as well as voltage and frequency dependent loads, respectively. In addition to this set of equations, the current phasor measurement is also represented as a function of the network state variables by (8), which is included in the proposed SE approach together with (5)-(7)…”

“…Despite that the state estimation has become a critical application function of the EMSs, there are only a few papers that include WTGs in this application [3][4][5][6]. The conventional and simplified resistance-reactance (R-X) models of a fixedspeed wind generator (FSWG) are adopted in [3,5] and [4,6], respectively, to estimate the slip of the asynchronous generators along with the nodal voltages using a centralized weighted least square-based (WLS) state estimator.…”

“…The conventional and simplified resistance-reactance (R-X) models of a fixedspeed wind generator (FSWG) are adopted in [3,5] and [4,6], respectively, to estimate the slip of the asynchronous generators along with the nodal voltages using a centralized weighted least square-based (WLS) state estimator. This kind of generator was the most commonly used in the early stages of wind power developments, but its use is expected to be reduced in future years due to the penetration of power electronic-based variable speed WTGs, which present higher efficiency and controllability [7].…”

ANN-based correlation of measurements in micro-grid state estimation

“…Using the theory for calculation of PV- [18,19,[26][27][28][29][30] and WT-based [4,18,19,24,28,31,32] internal (from primary energy resource) and output active powers, we identified the following weather parameters in PV-and WT-based input matrix (1), respectively: ; ;…”

“…Typically, applied approach uses different mathematical models that determine the relation between weather input data and internal active power of the DG unit [4,[28][29][30][31][32].…”