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.

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 An Improved Centralized Control Structure for Compensation of Voltage Distortions in Inverter-Based Microgrids

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1862 ◽  
Author(s):  
Morteza Afrasiabi ◽  
Esmaeel Rokrok
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Hierarchical Control ◽  
Control Level ◽  
Measurement Unit ◽  
Centralized Control ◽  
Secondary Control ◽  
Voltage Unbalance ◽  
Control Scheme ◽  
Centralized Controller

Recently, increased use of non-linear loads has intensified the harmonic distortion and voltage unbalance in distribution systems. Inverter Based Distributed Generators (IBDGs) can be employed as distributed compensators to improve the power quality, as well as to supply distribution systems. In this paper, an enhanced hierarchical control scheme for the compensation of voltage disturbance in an AC Micro Grid (MG) that includes of two control levels is proposed. The secondary control level is performed by a centralized controller. Data of voltage harmonics and voltage unbalance at the MG Sensitive Load Bus (SLB) is sent to the centralized controller by a measurement unit. A general case with a combined voltage harmonic and unbalance distortion is considered. The compensation coefficients for IBDG units are computed by the centralized controller, and reference commands are sent to the local controllers of the IBDG units that act as a primary level of control. In the secondary control level, harmonic analysis is performed for the MG in order to provide a guide for properly assigning the harmonics and unbalance compensation priorities to IBDGs at different locations in the distribution system. Some buses have more participation in exciting the MG resonance modes; therefore, larger harmonic compensation factors are considered for the IBDGs that are near to these buses. For other IBDGs, the voltage unbalance compensation factor is selected bigger. The control system of the IBDGs mainly includes a current controller, a virtual damping resistor loop, and a load compensation block. Effectiveness of the proposed control scheme is demonstrated through simulation studies.

scholarly journals ESTABLISHMENT AND PLACEMENT OF A MULTI-PURPOSE PHASOR MEASUREMENT UNIT TO IMPROVE PARALLEL STATE ESTIMATION IN DISTRIBUTION NETWORKS

2021 ◽  
Vol 3 (1) ◽  
pp. 1-17
Author(s):  
Zeyad Khashroum ◽  
Ali Dehghan Chaharabi ◽  
Lorena Palmero ◽  
Keiichiro Yasukawa
Keyword(s):  
State Estimation ◽  
Distribution Systems ◽  
Distribution Network ◽  
Distribution Networks ◽  
Phasor Measurement Unit ◽  
Measurement Unit ◽  
Optimal Method ◽  
Control Approach ◽  
Phasor Measurement ◽  
Neural Fuzzy

Today, microgrids in distribution networks are in dire need of improvement to cope with economic challenges, human losses, and equipment placement issues. Today, there is the issue of scattered resources in distribution systems, which has created many problems in the areas of environment, economy, and human and animal losses. The most important challenge in this section is the existence of voltage and frequency fluctuations during the occurrence of possible events such as severe load changes or errors in distribution networks. Having such a big problem can call a distribution network into question and destroy it. Therefore, it is necessary to provide an optimal method that can meet and cover these challenges. For this purpose, the present research deals with the problem of establishing and placing a multifunctional phasor measurement unit to improve the parallel state estimation in distribution networks, which offers a control approach. This approach determines the time of occurrence of internal and external disturbances after using the phasor unit. The approach of this research is to use a neural-fuzzy method because there is uncertainty in the distribution network due to the mentioned challenges, and training in the system is needed to accurately deploy and place possible errors. Do not occur. When setting up and placing the phasor measuring unit, the most important issue is the proper distribution of the load in the distribution network. The simulation results in the MATLAB / Simulink environment show the improvement of the results according to the proposed approach.Keywords: Distribution Network, Neural-Fuzzy Network, Optimal Load Distribution, Parallel State Estimation, Phasor Measurement Unit.

scholarly journals A Comprehensive Survey on Phasor Measurement Unit Applications in Distribution Systems

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4552 ◽  
Author(s):  
Mojgan Hojabri ◽  
Ulrich Dersch ◽  
Antonios Papaemmanouil ◽  
Peter Bosshart
Keyword(s):  
Power Systems ◽  
Data Quality ◽  
Distribution System ◽  
Distribution Systems ◽  
Measurement Unit ◽  
Wide Area Monitoring ◽  
Phasor Measurement ◽  
Comprehensive Survey ◽  
Measurement Units ◽  
Area Monitoring

Synchrophasor technology opens a new window for power system observability. Phasor measurement units (PMUs) are able to provide synchronized and accurate data such as frequency, voltage and current phasors, vibration, and temperature for power systems. Thus, the utilization of PMUs has become quite important in the fast monitoring, protection, and even the control of new and complicated distribution systems. However, data quality and communication are the main concerns for synchrophasor applications. This study presents a comprehensive survey on wide-area monitoring systems (WAMSs), PMUs, data quality, and communication requirements for the main applications of PMUs in a modern and smart distribution system with a variety of energy resources and loads. In addition, the main challenges for PMU applications as well as opportunities for the future use of this intelligent device in distribution systems will be presented in this paper.

A Method of Introducing PMU Current Measurement to Nonlinear State Estimation

2014 ◽  
Vol 960-961 ◽  
pp. 780-785 ◽  
Author(s):  
Zhao Kun ◽  
Yan Lei ◽  
Li Li ◽  
Qiang Li ◽  
Yan Sheng Lang ◽  
...  
Keyword(s):  
Data Acquisition ◽  
State Estimation ◽  
Supervisory Control ◽  
Small Error ◽  
Polar Coordinates ◽  
Phasor Measurement Unit ◽  
Estimation Accuracy ◽  
Measurement Unit ◽  
Nonlinear State Estimation ◽  
Nonlinear State

Aiming at the problem that the current measurements provided by phasor measurement unit (PMU) is difficult to introduce to traditional state estimation, a new method to solve the compatibility problems of PMU and supervisory control and data acquisition (SCADA) is presented in this paper. By the rotated-pseudo-measurement (RPM) method, current measurements are transformed into the pseudo measurements and decoupled in polar coordinates, so that they could taken into nonlinear state estimation. Then the RPM method is simulated compared with the current transformation (CT) method. According to the result, it is showed that the RPM method has many advantages compared with the CT, such as independence of other measurements, small error in propagation and more significant in improving estimation accuracy. Moreover, the RPM method has the compatibility with traditional nonlinear state estimation and the fast calculating speed, which have good prospects of practice.

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