scholarly journals A novel out of step relaying algorithm based on wavelet transform and a deep learning machine model

Author(s):  
Jigneshkumar Pramodbhai Desai ◽  
Vijay Hiralal Makwana

AbstractOut-of-step protection of one or a group of synchronous generators is unreliable in a power system which has significant renewable power penetration. In this work, an innovative out-of-step protection algorithm using wavelet transform and deep learning is presented to protect synchronous generators and transmission lines. The specific patterns are generated from both stable and unstable power swing, and three-phase fault using the wavelet transform technique. Data containing 27,008 continuous samples of 48 different features is used to train a two-layer feed-forward network. The proposed algorithm gives an automatic, setting free and highly accurate classification for the three-phase fault, stable power swing, and unstable power swing through pattern recognition within a half cycle. The proposed algorithm uses the Kundur 2-area system and a 29-bus electric network for testing under different swing center locations and levels of renewable power penetration. Hardware-in-the-loop (HIL) tests show the hardware compatibility of the developed out-of-step algorithm. The proposed algorithm is also compared with recently reported algorithms. The comparison and test results on different large-scale systems show that the proposed algorithm is simple, fast, accurate, and HIL tested, and not affected by changes in power system parameters.

2019 ◽  
Vol 100 ◽  
pp. 00057
Author(s):  
Elżbieta Niemierka ◽  
Piotr Jadwiszczak

Ever-increasing power market and environmental policy enforce growth of renewable power sources. Renewables inflexibility and dependency on weather condition causes periodically imbalance in power system due to the green power overproduction. With the increase of renewable sources, the balancing problems in power system will be increasingly significance issue. It is proposed to use individual heat pumps as a next tool for energy system adjustment support. Power system adjustment will be carried out by active demand side management by intended domestic hot water tanks overheating. The smart grid individual heat pumps setpoints will be switched at community or even country scale. The strategy allows shaving the overproduction peaks through short-term increase of electricity consumption in remote controlled heat pumps and to lowering power demand during green power deficits using the thermal energy stored in overheated domestic hot water. The dynamic mathematical simulations were made to define the operation and limitation of active control strategy of heat pumps integrated into smart grid. The results allow testing and assessing the potential of individual heat pumps as a next tool for balancing the power system with large scale of renewable power.


2014 ◽  
Vol 672-674 ◽  
pp. 227-232
Author(s):  
Xu Zhi Luo ◽  
Hai Feng Li ◽  
Hua Dong Sun ◽  
An Si Wang ◽  
De Zhi Chen

With the fast development of the wind power, security constraints of power systems have become the bottleneck of the acceptable capacity for wind power. The underdamping oscillation modes of the inter-area is an important aspect of the constraints. In this paper, an equivalent model of a power system with wind plants has been established, and the impact of the integration of the large-scale wind power on the inter-area oscillation modes has been studied based on the frequency-domain and time-domain simulations. The results indicate that the damping of inter-area oscillation mode can be enhanced by the replacement of synchronous generators (SGs) with the wind generators. The enhancing degree is up to the participation value of the SGs replaced. The conclusion has been verified by the actual system example of Xinjiang-Northwest grid. It can provide a reference for system programming and operation.


2019 ◽  
Vol 11 (3) ◽  
pp. 309-331
Author(s):  
Assist. Prof. Dr. Inaam I. ALI ◽  
Mohanad Sh. Tarad AL-AASAM

Preliminary studies on Iraqi power system show a significant increase in the short circuit level at some of the grid substations and some power stations. This increasing results from the growth of the power generation and transmission systems in size and complexity. Islanding or splitting is dividing the power system into several islands inorder to reduce short circuit levels and avoiding blackouts. The main islanding problem is determining the location of proper splitting points and load balance and satisfaction of transmission capacity constraints for each islands.This paper mainly introduces new proposed splitting strategies of large-scale power systems by using (PSS™E version 30.3 PACKAGE PROGRAME), such that, make re-interconnection of 400KV super high voltage substation based on three-phase load flow to be minimum flow at splitting point and infeed fault current details method to control short circuit levels in Iraq power system without islanding the power system into isolated islands. Controlled islanding or splitting scheme is frequently considered as the final solution to avoid blackouts of power system.Simulation IEEE-25 bus and Iraqi power system used as the test systems for this method. Furthermore, simulation results show significant effectiveness on reducing short circuit levels with same time give stable splitting islands with same frequency for preventing the system blackouts.


2017 ◽  
Vol 125 ◽  
pp. 207-213 ◽  
Author(s):  
Alexander Kies ◽  
Bruno Schyska ◽  
Dinh Thanh Viet ◽  
Lueder von Bremen ◽  
Detlev Heinemann ◽  
...  

Author(s):  
Kumarraja Andanapalli ◽  
Monalisa Biswal

Abstract Distance relay are designed with swing blocking/tripping logic to maintain reliable and secure operation of power system. To prevent this from happening, the relay is functioned with a power swing blocking (PSB) logic. However, ensuring proper detection to swing event requires to overcome from the dependable situation such as three-phase fault. The relay refuses to behave normally if both swing and three-phase fault occur simultaneously. Reliable setting is essential to generate trip/block command. Unsymmetrical faults are easily detected during the swing condition due to the presence of negative and zero sequence components, but such components are absent in the case of symmetrical/three-phase fault. As a result, symmetrical fault under blocking condition is unidentified many a times by the distance relay, arising security issues. To improve the relay operation during swing and symmetrical fault conditions, a MOPSVC (multiplication of positive sequence voltage and current) based index is developed in this work. The MOPSVC index helps to discern power swing from three-phase fault. To test the efficacy of the method, a 230 kV, 50 Hz two-area four machine system, and Indian Eastern Regional Grid (IERG) network are considered. Simulation task is conducted using EMTDC/PSCAD software. To investigate the performance of the proposed method, various swing phenomena, faults, CT saturation, switching transients, and the presence of noise cases are considered, and the results demonstrate the robustness of the proposed algorithm. Responses under stressed power system conditions are also investigated, and a report on comparisons with existing methods is provided. Simulated results confirm that the proposed algorithm can balance the dependability and security aspects of the protection logic.


Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1525 ◽  
Author(s):  
Omid Rahbari ◽  
Noshin Omar ◽  
Joeri Van Mierlo ◽  
Marc A. Rosen ◽  
Thierry Coosemans ◽  
...  

Electric vehicles (EVs) are recognized as promising options, not only for the decarbonization of urban areas and greening of the transportation sector, but also for increasing power system flexibility through demand-side management. Large-scale uncoordinated charging of EVs can impose negative impacts on the existing power system infrastructure regarding stability and security of power system operation. One solution to the severe grid overload issues derived from high penetration of EVs is to integrate local renewable power generation units as distributed generation units to the power system or to the charging infrastructure. To reduce the uncertainties associated with renewable power generation and load as well as to improve the process of tracking Pareto front in each time sequence, a predictive double-layer optimal power flow based on support vector regression and one-step prediction is presented in this study. The results demonstrate that, through the proposed control approach, the rate of battery degradation is reduced by lowering the number of cycles in which EVs contribute to the services that can be offered to the grid via EVs. Moreover, vehicle to grid services are found to be profitable for electricity providers but not for plug-in electric vehicle owners, with the existing battery technology and its normal degradation.


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