An Improved Three-Phase AMB Distribution System State Estimator

Abstract

State estimators (SEs) are required to enable the evolving and increasingly important role of communications and control in smart distribution systems. In this context, this paper presents an improved three-phase admittance matrix-based (AMB) SE for medium voltage systems to tackle issues related to zero injections, consistency, and the inclusion of voltage measurements. Here, the state variables are the real and imaginary parts of the complex bus voltages, while power and voltage measurements are converted into equivalent currents and voltages, respectively. The key improvements include: (i) considering zero injections through a linear non-weighted procedure, (ii) using phasor rotation for calculation of the equivalent voltage measurements, and, (iii) including the covariance between real and imaginary parts of equivalent current measurements. Despite these new characteristics, the proposed improved AMB SE (ISE) features constant coefficient matrices, thus resulting in reduced computational times. The performance of the ISE is assessed considering a real UK medium voltage system. Its consistency is assessed via a Monte Carlo analysis. Comparisons with other AMB SEs, demonstrate that the proposed three-phase ISE is more robust, statistically more consistent and computationally very competitive.  This work has been partially funded by FAPESP, CNPq and CAPES.

Two-Stage Linear Three-Phase State Estimation Formulation for Active Distribution Network

“…Three-phase unbalance network constraints and configuration should be considered carefully in distribution SE [10][11][12][13], include Delta connection devices, floating point network, zero injection nodes. With proper network dimmesion reduction, distribution network SE with large scale zero injection nodes can be effecitively improved [11].…”

“…With proper network dimmesion reduction, distribution network SE with large scale zero injection nodes can be effecitively improved [11].…”

“…Step 5: Carry out three-phase AMB SE [11]. This step is necessary for SE results to satisfy more strict network constraints.…”

Análise de Padrões de Esparsidade e Métodos de Ordenação para Estimação de Estado em Sistemas de Distribuição

“…Um desses algoritmos utiliza, ao invés da tensão nodal na forma polar, a corrente nos ramos na forma retangular como o apresentado por Pal et al (2013). Outra formulação, baseada na matriz admitância do sistema foi proposta por Almeida and Ochoa (2017). Apesar de apresentarem resultados aderentes para sistemas radiais de média tensão, estas abordagens ainda sofrem de ressalvas teóricas, visto que se baseiam em aproximações do modelo de medição original para representar as medidas através de equivalentes de corrente.…”

Specifying angular reference for three‐phase distribution system state estimators

“…The so‐called admittance matrix‐based SE (AMB‐SE) [12–17] adopts the real and imaginary parts of the complex bus voltages as state variables, while active and reactive power measurements are converted into equivalent current measurements (ECM), resulting in a constant Gain matrix. This method has proven to be fairly consistent [18, 24]. A similar DSSE adopting the real and imaginary parts of the complex branch currents as state variables and the concept of ECM, resulting in a constant Gain matrix, is presented in [19–22].…”