Multi-Phase State Estimation Featuring Industrial-Grade Distribution Network Models

Abstract

Abstract-This paper proposes a novel implementation of a multi-phase distribution network state estimator which employs industrial-grade modeling of power components and measurements. Unlike the classical voltage-based and current-based state estimators, this paper presents the implementation details of a constrained weighted least squares state calculation method that includes standard three-phase state estimation capabilities in addition to practical modeling requirements from the industry; these requirements comprise multi-phase line configurations, unsymmetrical and incomplete transformer connections, power measurements on -connected loads, cumulative-type power measurements, line-to-line voltage magnitude measurements, and reversible line drop compensators. The enhanced modeling equips the estimator with capabilities that make it superior to a recently presented state-of-the-art distribution network load estimator that is currently used in real-life distribution management systems; comparative performance results demonstrate the advantage of the proposed estimator under practical measurement schemes.Index Terms-Power distribution, power system modeling, power system simulation, state estimation. Λ (i)Set of nodes connected to node i by a branch. COM P Set (with structure (φ, ij)) of phases in transformer branches having line drop compensators; φ ∈ {a, b, c} for a regulator on the Y-connected side and φ ∈ {ab, bc, ca} for a regulator on the ∆-connected side. CTP /CTS Primary/seconday current ratio of the current transformer in the compensator circuit.Base current in the compensator circuit, corresponding to the base current in the line circuit LP QSet (with structure (φ, i)) of phases at all the nodes with real/reactive load power; φ ∈ {a, b, c} for Y-connected loads and φ ∈ {ab, bc, ca} for ∆-connected loads. M BCSet (with structure (φ, ij)) of phases in the branches with current magnitude measurements; φ ∈ {a, b, c}. M BP Set (with structure (φ, ij)) of phases in the branches with real power flow measurements; φ ∈ {a, b, c}. M BQ Set (with structure (φ, ij)) of phases in the branches with reactive power flow measurements; φ ∈ {a, b, c}. M CU M P Set of branches with cumulative real power flow measurements. M CU M Q Set of branches with cumulative reactive power flow measurements. M LGVSet (with structure (φ, i)) of phases at the nodes with line-to-ground voltage magnitude measurements; φ ∈ {a, b, c}. M LLVSet (with structure (φ, i)) of phases at the nodes with line-to-line voltage magnitude measurements; φ ∈ {ab, bc, ca}.Primary/seconday turns ratio of the potential transformer in the compensator circuit. NSet of all nodes; N (i) is the set of phases (out of a, b, c) at node i. P φ ijReal power flow in phase φ of branch ij; φ ∈ {a, b, c}. P CU M ijCumulative real power flow in branch ij. P φ LiReal load power consumed in phase φ at node i; φ ∈ {a, b, c} for Y-connected loads and φ ∈ {ab, bc, ca} for ∆-connected loads. This article has been accepted for publication in a future issue of this journal, but ...

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