scholarly journals Interval State Estimation in Active Distribution Systems Considering Multiple Uncertainties

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4644
Author(s):  
Tengpeng Chen ◽  
He Ren ◽  
Gehan A. J. Amaratunga
Keyword(s):  
State Estimation ◽  
Distribution System ◽  
Distribution Systems ◽  
Constraint Propagation ◽  
Upper And Lower Bounds ◽  
Krawczyk Operator ◽  
Multiple Uncertainties ◽  
Conservative Estimation ◽  
Power Outputs ◽  
Non Gaussian

Distribution system state estimation (DSSE) plays a significant role for the system operation management and control. Due to the multiple uncertainties caused by the non-Gaussian measurement noise, inaccurate line parameters, stochastic power outputs of distributed generations (DG), and plug-in electric vehicles (EV) in distribution systems, the existing interval state estimation (ISE) approaches for DSSE provide fairly conservative estimation results. In this paper, a new ISE model is proposed for distribution systems where the multiple uncertainties mentioned above are well considered and accurately established. Moreover, a modified Krawczyk-operator (MKO) in conjunction with interval constraint-propagation (ICP) algorithm is proposed to solve the ISE problem and efficiently provides better estimation results with less conservativeness. Simulation results carried out on the IEEE 33-bus, 69-bus, and 123-bus distribution systems show that the our proposed algorithm can provide tighter upper and lower bounds of state estimation results than the existing approaches such as the ICP, Krawczyk-Moore ICP(KM-ICP), Hansen, and MKO.

State Estimation of Active Distribution Networks

2020 ◽  
pp. 270-308
Author(s):  
Razan Al Rhia ◽  
Haithm Daghrour
Keyword(s):  
State Estimation ◽  
Distribution System ◽  
Distribution Systems ◽  
Operating Performance ◽  
Distribution Networks ◽  
Dynamic State ◽  
State Estimator ◽  
Static State ◽  
Active Distribution Networks

Monitoring and controlling the electrical distribution system for real time is becoming very important to improve its operating performance after transition to active distribution systems. So, many sensors are needed to monitor all parts in the systems. But if sensors are installed at all buses, investment cost becomes huge. To reduce the number of sensors, state estimation approach can be used to estimate the voltage of buses, which do not have sensors. State Estimation (SE) algorithms are broadly classified into Static State Estimator (SSE) and Dynamic State Estimator (DSE). This chapter classifies most algorithms used in active distribution networks, also State estimation in unbalanced distribution systems, and Role of PMU in Distribution System State Estimation.

scholarly journals Bayesian Approach for Distribution System State Estimation With Non-Gaussian Uncertainty Models

2017 ◽  
Vol 66 (11) ◽  
pp. 2957-2966 ◽  
Author(s):  
Paolo Attilio Pegoraro ◽  
Andrea Angioni ◽  
Marco Pau ◽  
Antonello Monti ◽  
Carlo Muscas ◽  
...  
Keyword(s):  
State Estimation ◽  
Bayesian Approach ◽  
Distribution System ◽  
System State ◽  
Non Gaussian ◽  
Uncertainty Models

scholarly journals Optimal Selection of Metering Points for Power Quality Measurements in Distribution System

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1202
Author(s):  
Krzysztof Piatek ◽  
Andrzej Firlit ◽  
Krzysztof Chmielowiec ◽  
Mateusz Dutka ◽  
Szymon Barczentewicz ◽  
...  
Keyword(s):  
State Estimation ◽  
Power Quality ◽  
Power Distribution ◽  
Distribution System ◽  
Distribution Systems ◽  
Optimal Selection ◽  
Power Distribution Systems ◽  
Observability Analysis ◽  
Selection Of

Quality of power supply in power distribution systems requires continuous measurement using power quality analyzers installed in the grid. The paper reviews the published methods for optimal location of metering points in distribution systems in the context of power quality metering and assessment. Three methods have been selected for detailed analysis and comparative tests. It has been found that utilization of the methods is possible, but their performance varies highly depending on the test grid’s topology. Since the methods rely on the state estimation approach, their performance is strictly related to observability analysis. It has been found that standard observability analysis used for typical state estimation problem yields ambiguous results when applied to power quality assessment. Inherited properties of the selected methods are also analyzed, which allows for the formulation of general recommendations about optimal selection of metering points in a distribution system.

scholarly journals Compensated Load Flow Solutions for Distribution System State Estimation

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3100 ◽  
Author(s):  
Catalina Gómez-Quiles ◽  
Esther Romero-Ramos ◽  
Antonio de la Villa-Jaén ◽  
Antonio Gómez-Expósito
Keyword(s):  
State Estimation ◽  
Distribution System ◽  
Distribution Systems ◽  
Jacobian Matrix ◽  
Accurate Estimate ◽  
Load Flow ◽  
System State ◽  
Critical Set ◽  
Estimation Of Distribution ◽  
Ill Conditioning

State estimation of distribution systems typically relies on measurement sets with very low redundancy levels. In this paper, this fact is exploited by first solving a conventional load flow, using exclusively a critical set of measurements, and then compensating the solution to account for the few redundant measurements available. This leads to a suboptimal but sufficiently accurate estimate. It is shown how the sparse triangular factorization of the load flow Jacobian matrix can be fully exploited throughout the compensation-based procedure, preventing in this way the ill-conditioning associated with the gain matrix arising in the conventional least-squares formulation. Simulation results are provided for measurement configurations customarily found in distribution systems, showing the potential advantages of the proposed methodology.

scholarly journals The Challenges of Low Voltage Distribution System State Estimation—An Application Oriented Review

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5363
Author(s):  
István Táczi ◽  
Bálint Sinkovics ◽  
István Vokony ◽  
Bálint Hartmann
Keyword(s):  
State Estimation ◽  
Distribution System ◽  
Distribution Systems ◽  
Low Voltage ◽  
Early Stage ◽  
Renewable Energy Sources ◽  
General Structure ◽  
Theory And Practice ◽  
System State ◽  
Time Operation

Global trends such as the growing share of renewable energy sources in the generation mix, electrification, e-mobility, and the increasing number of prosumers reshape the electricity value chain, and distribution systems are necessarily affected. These systems were planned, developed, and operated as a passive structure for decades with low level of observability. Due to the increasing number of system states, real time operation planning and flexibility services are the key in transition to an active grid management. In this pathway, distribution system state estimation (DSSE) has a great potential, but the real demonstration of this technique is in an early stage, especially on low-voltage level. This paper focuses on the gap between theory and practice and summarizes the limits of low-voltage DSSE implementation. The literature and the main findings follow the general structure of a state estimation process (meter placement, bad data detection, observability, etc.) giving a more essential and traceable overview structure. Moreover, the paper provides a comprehensive mapping of the possible use-cases state estimation and evaluates 27 different experimental sites to conclude on the practical applicability aspects.

scholarly journals A Hybrid State Estimator Based on SCADA and PMU Measurements for Medium Voltage Distribution System

2018 ◽  
Vol 8 (9) ◽  
pp. 1527 ◽  
Author(s):  
Xiangyu Kong ◽  
Ying Chen ◽  
Tao Xu ◽  
Chengshan Wang ◽  
Chengsi Yong ◽  
...  
Keyword(s):  
Data Acquisition ◽  
State Estimation ◽  
Robust Estimation ◽  
Distribution System ◽  
Distribution Systems ◽  
Measurement Unit ◽  
State Estimator ◽  
Hybrid State ◽  
Linear State ◽  
And Performance

With the increasing importance of renewable energy and flexible loads, the operation of the distribution system is becoming more stochastic and complex, and it is necessary to monitor the power system in real-time. Considering the gradual applications of intelligent electronic devices in the distribution systems, a hybrid state estimator based on supervisory control and data acquisition (SCADA) and phasor measurement unit (PMU) measurements is proposed in this paper, which consists of the improved robust estimation and linear state estimation. At the time of SCADA data acquisition, the improved robust estimation combining the SCADA measurements with PMU measurements is performed. To eliminate the effect of bad data, the internal student residual method is introduced, and the robust thresholds are adjusted adaptively. Then the linear state estimation is performed at the time of PMU data acquisition based on the results of the previous estimation time and the PMU measurements, which can quickly correct the robust estimation results and track the changes of the distribution system. Finally, the effectiveness and performance of the proposed method are verified in a modified IEEE 33-bus distribution system and a real distribution system in China.

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