scholarly journals μPMU-Based Temporal Decoupling of Parameter and Measurement Gross Error Processing in DSSE

Electricity ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 423-438
Author(s):  
Rodrigo D. Trevizan ◽  
Cody Ruben ◽  
Aquiles Rossoni ◽  
Surya C. Dhulipala ◽  
Arturo Bretas ◽  
...  
Keyword(s):  
Error Analysis ◽  
Distribution System ◽  
Test System ◽  
Recent Measurement ◽  
Test Results ◽  
State Estimator ◽  
Smart Meters ◽  
Gross Error ◽  
Processing Step ◽  
Linear State

Simultaneous real-time monitoring of measurement and parameter gross errors poses a great challenge to distribution system state estimation due to usually low measurement redundancy. This paper presents a gross error analysis framework, employing μPMUs to decouple the error analysis of measurements and parameters. When a recent measurement scan from SCADA RTUs and smart meters is available, gross error analysis of measurements is performed as a post-processing step of non-linear DSSE (NLSE). In between scans of SCADA and AMI measurements, a linear state estimator (LSE) using μPMU measurements and linearized SCADA and AMI measurements is used to detect parameter data changes caused by the operation of Volt/Var controls. For every execution of the LSE, the variance of the unsynchronized measurements is updated according to the uncertainty introduced by load dynamics, which are modeled as an Ornstein–Uhlenbeck random process. The update of variance of unsynchronized measurements can avoid the wrong detection of errors and can model the trustworthiness of outdated or obsolete data. When new SCADA and AMI measurements arrive, the LSE provides added redundancy to the NLSE through synthetic measurements. The presented framework was tested on a 13-bus test system. Test results highlight that the LSE and NLSE processes successfully work together to analyze bad data for both measurements and parameters.

Selection of an Efficient Linear State Estimator for Unified Real Time Dynamic State Estimation in Indian Smart Grid

2019 ◽  
Vol 20 (4) ◽  
Author(s):  
Naheed Mobin ◽  
Mohd Rihan ◽  
Mohd Zuhaib
Keyword(s):  
Smart Grid ◽  
State Estimation ◽  
Real Time ◽  
Power Grid ◽  
Dynamic State ◽  
Test Results ◽  
State Estimator ◽  
Time Dynamic ◽  
Linear State ◽  
Selection Of

Abstract As electricity demand is continuously increasing, the complexity and criticality of the power system infrastructure is increasing. After suffering from world’s largest power blackout on 30th and 31st July, 2012, the Indian power grids are now adopting the smart grid technologies to prevent such massive power failures. It initiated with the installation of PMUs on each strategically selected critical location in the entire grid under the Real Time Dynamic State measurements (URTDSM) scheme to attain the complete observability of the system. However, attainment of complete observability further demands selection of accurate and fast SE algorithm which is still a challenging task. The aim of this paper is to recommend the most efficient and accurate state estimator based on Linear State Estimation (LSE) algorithms for efficient real time monitoring and control of the grid, especially for Indian Power Grid. The performance test was conducted on two different SE algorithms, the Weighted Least Square (WLS) algorithm and recursive Kalman Filter algorithm. The test results are obtained on Indian 75-bus transmission system and validation is done by comparing the test results with the results obtained on standard IEEE-39 bus test system. Based on the performance comparison of the two algorithms, the selection of most suitable algorithm to be implemented in Indian power grid is achieved.

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.

Evaluation of the disinfection potential of low chlorine concentrations in tap water using immobilised enterococcus faecium in a continuous flow device

1997 ◽  
Vol 35 (11-12) ◽  
pp. 77-80 ◽  
Author(s):  
A. Wiedenmann ◽  
M. Braun ◽  
K. Botzenhart
Keyword(s):  
Distribution System ◽  
Enterococcus Faecium ◽  
Continuous Flow ◽  
Tap Water ◽  
Test System ◽  
Batch Experiments ◽  
Membrane Filters ◽  
Upper Limit ◽  
Flow Device ◽  
Faecal Streptococci

A simple continuous flow device in which bacteria were immobilised on membrane filters and flushed with tap water with free chlorine residuals of 0.05, 0.1, 0.2 and 0.4mg/L at pH 7.7 and 10°C, has been used for disinfection experiments with faecal streptococci. A 99.99% reduction of Enterococcus faecium was observed between 3.4–5.2min (0.05mg/L), between 2.8–4.1min (0.1mg/L), between 1.7–3.1min (0.2mg/L) and between 0.8–2.1min (0.4mg/L). CT-products covered a range of 0.17 (0.05mg/L, lower limit) up to 0.85mg/L/min (0.4mg/L, upper limit). The test system is suggested as a more reliable alternative to batch experiments when the disinfection potential of low chlorine concentrations acting for several minutes has to be evaluated. The system cannot be used to demonstrate exact reduction kinetics but it allows the calculation of CT values and the evaluation of the disinfection potential of chlorinated water at any point of a distribution system where initial chlorine concentrations may have already remarkably declined.

Framework and performance analysis of college English testing system based on data mining technology

2021 ◽  
pp. 1-11
Author(s):  
Liu Narengerile ◽  
Li Di ◽  
Keyword(s):  
Data Mining ◽  
Test System ◽  
Test Time ◽  
Testing System ◽  
Test Results ◽  
System Software ◽  
Examination System ◽  
Mining Technology ◽  
College English ◽  
And Performance

At present, the college English testing system has become an indispensable system in many universities. However, the English test system is not highly humanized due to problems such as unreasonable framework structure. This paper combines data mining technology to build a college English test framework. The college English test system software based on data mining mainly realizes the computer program to automatically generate test papers, set the test time to automatically judge the test takers’ test results, and give out results on the spot. The test takers log in to complete the test through the test system software. The examination system software solves the functions of printing test papers, arranging invigilation classrooms, invigilating teachers, invigilating process, collecting test papers, scoring and analyzing test papers in traditional examinations. Finally, this paper analyzes the performance of this paper through experimental research. The research results show that the system constructed in this paper has certain practical effects.

scholarly journals Leveraging a Genetic Algorithm for the Optimal Placement of Distributed Generation and the Need for Energy Management Strategies Using a Fuzzy Inference System

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 172
Author(s):  
Sunny Katyara ◽  
Muhammad Fawad Shaikh ◽  
Shoaib Shaikh ◽  
Zahid Hussain Khand ◽  
Lukasz Staszewski ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Energy Management ◽  
Fuzzy Inference System ◽  
Distribution System ◽  
Fuzzy Inference ◽  
Management Strategies ◽  
Test System ◽  
Optimal Placement ◽  
Inference System ◽  
Simulated Environment

With the rising load demand and power losses, the equipment in the utility network often operates close to its marginal limits, creating a dire need for the installation of new Distributed Generators (DGs). Their proper placement is one of the prerequisites for fully achieving the benefits; otherwise, this may result in the worsening of their performance. This could even lead to further deterioration if an effective Energy Management System (EMS) is not installed. Firstly, addressing these issues, this research exploits a Genetic Algorithm (GA) for the proper placement of new DGs in a distribution system. This approach is based on the system losses, voltage profiles, and phase angle jump variations. Secondly, the energy management models are designed using a fuzzy inference system. The models are then analyzed under heavy loading and fault conditions. This research is conducted on a six bus radial test system in a simulated environment together with a real-time Power Hardware-In-the-Loop (PHIL) setup. It is concluded that the optimal placement of a 3.33 MVA synchronous DG is near the load center, and the robustness of the proposed EMS is proven by mitigating the distinct contingencies within the approximately 2.5 cycles of the operating period.

Model-Based Discrete Linear State Estimator for Nonlinearizable Systems With State-Dependent Noise

1990 ◽  
Vol 112 (4) ◽  
pp. 774-781 ◽  
Author(s):  
R. J. Chang
Keyword(s):  
Discrete Time ◽  
Continuous Model ◽  
Equivalent Model ◽  
State Estimator ◽  
Time Model ◽  
State Dependent ◽  
Present Technique ◽  
Linear State ◽  
Noisy Measurement ◽  
Time Linear

A practical technique to derive a discrete-time linear state estimator for estimating the states of a nonlinearizable stochastic system involving both state-dependent and external noises through a linear noisy measurement system is presented. The present technique for synthesizing a discrete-time linear state estimator is first to construct an equivalent reference linear model for the nonlinearizable system such that the equivalent model will provide the same stationary covariance response as that of the nonlinear system. From the linear continuous model, a discrete-time state estimator can be directly derived from the corresponding discrete-time model. The synthesizing technique and filtering performance are illustrated and simulated by selecting linear, linearizable, and nonlinearizable systems with state-dependent noise.

The Research of IC Test Based on LTX-77 Test System

2014 ◽  
Vol 496-500 ◽  
pp. 1176-1179
Author(s):  
Li Tan ◽  
Yu Fang
Keyword(s):  
Test Object ◽  
Test System ◽  
Test Method ◽  
Test Results ◽  
Analog Ic ◽  
Test Platform ◽  
Logic Functions ◽  
Actual Test ◽  
Ic Test

LTX-77 test system is a large IC test system that is used for various kinds of analog IC, digital IC and analog digital mixed IC. It can be used to test DC parameters, AC parameters and logic functions. In the paper, the IC test platform is LTX-77 test system. IC ADC0804 was tested as the test object. The test method of IC is described in the view of actual test. The test results show that the test system is convenient and accurate, which has important practical value for IC manufacturers and users.

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