scholarly journals Full-Observable Three-Phase State Estimation Algorithm Applied to Electric Distribution Grids

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1327 ◽  
Author(s):  
Thiago Soares ◽  
Ubiratan Bezerra ◽  
Maria Tostes
Keyword(s):  
State Estimation ◽  
Real Time ◽  
Distribution Systems ◽  
Phase State ◽  
Reactive Power ◽  
Estimation Algorithm ◽  
Load Flow ◽  
Electrical Network ◽  
The Real ◽  
Three Phase

This paper proposes the development of a three-phase state estimation algorithm, which ensures complete observability for the electric network and a low investment cost for application in typical electric power distribution systems, which usually exhibit low levels of supervision facilities and measurement redundancy. Using the customers´ energy bills to calculate average demands, a three-phase load flow algorithm is run to generate pseudo-measurements of voltage magnitudes, active and reactive power injections, as well as current injections which are used to ensure the electrical network is full-observable, even with measurements available at only one point, the substation-feeder coupling point. The estimation process begins with a load flow solution for the customers´ average demand and uses an adjustment mechanism to track the real-time operating state to calculate the pseudo-measurements successively. Besides estimating the real-time operation state the proposed methodology also generates nontechnical losses estimation for each operation state. The effectiveness of the state estimation procedure is demonstrated by simulation results obtained for the IEEE 13-bus test network and for a real urban feeder.

scholarly journals Three-Phase State Estimation for Distribution-Grid Analytics

2021 ◽  
Vol 3 (2) ◽  
pp. 395-408
Author(s):  
Karthikeyan Nainar ◽  
Florin Iov
Keyword(s):  
State Estimation ◽  
Phase State ◽  
Low Voltage ◽  
Real Life ◽  
Estimation Algorithm ◽  
Smart Meter ◽  
Power Losses ◽  
Distribution Grid ◽  
Three Phase ◽  
Distribution Grids

Power-distribution grids consist of assets such as transformers, cables, and switches, of which the proper utilization is essential for the provision of a secure and reliable power supply to end customers. Distribution-system operators (DSOs) are responsible for the operation and maintenance of these assets. Due to the increased use of renewable sources such as wind and solar, grid assets are prone to operation conditions outside safe boundaries, such as overloading, large voltage unbalance, and a rise in voltage. At present, distribution grids are poorly monitored by DSOs, and the above-mentioned problems may thereby go unnoticed until the failure of a critical asset occurs. The deployment of smart meters in distribution grids has enabled measurements of grid variables such as power, current, and voltage. However, their measurements are used only for billing purposes, and not for monitoring and improving the operating condition of distribution grids. In this paper, a state-estimation algorithm is proposed that utilizes smart-meter data for offline analysis, and estimates the loading of grid assets and power losses. Single- and three-phase state-estimation algorithms are compared through simulation studies on a real-life low-voltage distribution grid using measured smart-meter data. The three-phase state-estimation algorithm based on the nonlinear weighted least-squares method was found to be more accurate in estimating cable loading and line power losses. The proposed method is useful for DSOs to analyze power flows in their distribution grids and take necessary actions such as grid upgrades or the rerouting of power flows.

scholarly journals Application of State Estimation in Distribution Systems with Embedded Microgrids

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7933
Author(s):  
Nikolaos M. Manousakis ◽  
George N. Korres
Keyword(s):  
State Estimation ◽  
Real Time ◽  
Distributed Generation ◽  
Distribution Systems ◽  
Operation Mode ◽  
Estimation Algorithm ◽  
Distribution Networks ◽  
Least Square ◽  
Islanded Operation ◽  
The Impact

In this paper, a weighted least square (WLS) state estimation algorithm with equality constraints is proposed for smart distribution networks embedded with microgrids. Since only a limited number of real-time measurements are available at the primary or secondary substations and distributed generation sites, load estimates at unmeasured buses remote from the substations are needed to execute state estimation. The load information can be obtained by forecasted and historical data or smart real-time meters. The proposed algorithms can be applied in either grid-connected or islanded operation mode and can efficiently identify breaker status errors at the main substations and feeders, where sufficient measurement redundancy exists. The impact of the accuracy of real and pseudo-measurements on the estimated bus voltages is tested with a 55-bus distribution network including distributed generation.

scholarly journals Three-Phase State Estimation of a Low-Voltage Distribution Network with Kalman Filter

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7421
Author(s):  
Fabio Napolitano ◽  
Juan Diego Rios Penaloza ◽  
Fabio Tossani ◽  
Alberto Borghetti ◽  
Carlo Alberto Nucci
Keyword(s):  
Kalman Filter ◽  
State Estimation ◽  
Phase State ◽  
Low Voltage ◽  
Distribution Network ◽  
Estimation Algorithm ◽  
The State ◽  
Voltage Distribution ◽  
Smart Meters ◽  
Three Phase

The state estimation of distribution networks has long been considered a challenging task for the reduced availability of real-time measures with respect to the transmission network case. This issue is expected to be improved by the deployment of modern smart meters that can be polled at relatively short time intervals. On the other hand, the management of the information coming from many heterogeneous meters still poses major issues. If low-voltage distribution systems are of interest, a three-phase formulation should be employed for the state estimation due to the typical load imbalance. Moreover, smart meter data may not be perfectly synchronized. This paper presents the implementation of a three-phase state estimation algorithm of a real portion of a low-voltage distribution network with distributed generation equipped with smart meters. The paper compares the typical state estimation algorithm that implements the weighted least squares method with an algorithm based on an iterated Kalman filter. The influence of nonsynchronicity of measurements and of delays in communication and processing is analyzed for both approaches.

scholarly journals Methodology of Adaptive Instantaneous Overcurrent Protection Setting

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2754
Author(s):  
Saul Jimenez ◽  
Ernesto Vázquez ◽  
Francisco Gonzalez-Longatt
Keyword(s):  
Real Time ◽  
Linear Equations ◽  
Time Estimation ◽  
Estimation Algorithm ◽  
Positive Sequence ◽  
Electrical Network ◽  
The Real ◽  
Overcurrent Protection ◽  
Real Time Estimation ◽  
Non Linear Equations

This paper proposed a methodology of adaptive instantaneous overcurrent protection (AIOCP) setting that ensures that the protection coverage remains unchanged regardless of the operating condition of the electrical network. The methodology calculates the protection setting parameters based on the real-time estimation of the Thevenin equivalent circuit (TEC). The estimation algorithm uses the positive-sequence voltage and current values and a system of non-linear equations, which is solved iteratively by the Gauss–Newton method. The proposed methodology calculates the IOCP settings in real time by using the real-time estimation of the TEC; therefore, any change in the electric network conditions is represented in the TEC, and the calculated setting keeps the desired protection coverage constant. Simulation results demonstrate that the proposed AIOCP can keep constant the protection coverage overcoming the classical problems of classical IOCP: sub-allocation and over-coverage.

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