Loss Of Excitation (LOE) Protection of Synchronous Generator

2017 ◽  
Vol 8 (1) ◽  
pp. 230 ◽  
Author(s):  
Hui Hwang Goh ◽  
Sy yi Sim ◽  
Mohd. Nasri Abd Samat ◽  
Ahmad Mahmoud Mohamed ◽  
Chin Wan Ling ◽  
...  
Keyword(s):  
Reactive Power ◽  
Harmful Effect ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Financial Cost ◽  
New Techniques ◽  
Power Generator ◽  
Grid Systems ◽  
Protection Scheme ◽  
Power Swing

<p>Synchronous generators require certain protection against loss of excitation because it can lead to harmful effect to a generator and main grid. Systems of powers are evolving with applications of new techniques to increase reliability and security, at the meantime techniques upgradation is being existed to save financial cost of a different component of power system, which affect protection ways this report discuss the way of loss of excitation protection scheme for an increase in a synchronous generator. It is obvious that when direct axis synchronous reactance has a high value, the coordination among loss of excitation protection and excitation control is not effective. This lead to restricting absorption capability of the reactive power generator. This report also reviews the suitable philosophy for setting the limiters of excitation and discusses its effect on loss of excitation protection and system performance. A protection scheme is developed to allow for utilization of machine capability and power swing blocking is developed to increase the reliability when power swing is stable.</p><p><em> </em></p>

Distance Relaying with Power Swing Detection based on Voltage and Reactive Power Sensitivity

2016 ◽  
Vol 17 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Ujjaval J. Patel ◽  
Nilesh G. Chothani ◽  
Praghnesh J. Bhatt
Keyword(s):  
Reactive Power ◽  
Synchronous Generator ◽  
Power Input ◽  
Parallel Line ◽  
Rate Of Change ◽  
Electrical Network ◽  
Distance Relay ◽  
Heavy Load ◽  
Power Swing ◽  
Distance Relaying

Abstract Sudden changes in loading or configuration of an electrical network causes power swing which may result in an unwanted tripping of the distance relay. Hence, it becomes utmost necessary to rapidly and reliably discriminate between actual fault and power swing conditions in order to prevent instability in power network due to mal operation of distance relay. This paper proposes a novel method for the discrimination between fault and power swing based on rate of change of voltage and reactive power measured at relay location. The effectiveness of the proposed algorithm is evaluated by simulating series of power swing conditions in PSCAD/EMTDC® software for different disturbances such as change in mechanical power input to synchronous generator, tripping of parallel line due to fault and sudden application of heavy load. It is revealed that the distance relay gives successful tripping in case of different fault conditions and remains inoperative for power swing with the implementation of the proposed algorithm. Moreover, the proposed scheme has ability to distinguish the symmetrical and asymmetrical fault occurrence during power swing condition.

scholarly journals Simulation of wind power plant with double-fed machine when operating in autonomous system in parallel with synchronous commensurable power generator

2020 ◽  
Vol 178 ◽  
pp. 01034
Author(s):  
Rauf Mustafayev ◽  
Laman Hasanova
Keyword(s):  
Power Plant ◽  
Wind Power ◽  
Autonomous System ◽  
Power Transmission ◽  
Synchronous Generator ◽  
Wind Power Plant ◽  
Synchronous Generators ◽  
Transmission Scheme ◽  
Power Generator ◽  
Asynchronous Generator

Autonomous system, containing synchronous generators in a classic design, driven by either diesel or gas turbine, which operates in parallel with a wind power plant (WPP) containing an asynchronous double-fed machine (ADFM) through external network, is considered in the paper. At the same time, the power transmission scheme and the corresponding equivalent circuit are also drawn up. The equations of the synchronous generator and the external network are written in the axes rotating at the speed of the synchronous generator rotor, and the equations of the WPP’s generator in the axes rotating at the speed of its rotor. By means of “docking” equations a digital model of the entire system is compiled with the external network parameters and loads on the side of the synchronous generator and WPP’s asynchronous generator, which are represented by constant-conductivity shunts. Static and dynamic characteristics of the system are calculated.

scholarly journals ANALISA PROTEKSI HILANG EKSITASI PADA GENERATOR SINKRON DI PLTGU MUARA TAWAR GT UNIT 1.3

Sutet ◽  
1970 ◽  
Vol 7 (2) ◽  
pp. 124-132
Author(s):  
Redaksi Tim Jurnal
Keyword(s):  
Delay Time ◽  
Reactive Power ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Protection System ◽  
Power Generator ◽  
The Future ◽  
The Impact

One of the operating disruptions that occur in the synchronous generator is the loss of excitation. Where this interference will cause the generated reactive power generator is reduced even lost so that the synchronous generator must absorb the reactive power of the system. If this condition occurs continuously can cause damage to the stator coil, will occur worsening insulation and the stator end iron so as to cause short circuit, or interruption of soil relations in the future. So to anticipate the impact of such disturbances required a protection system. The protection system used in PLTGU Muara Tawar GT unit 1.3 is a minimum reactance relay. This jurnal discusses how to determine the value of loss excitation protection setting using minimum reactance relay and offset relay mho so that synchronous generator can work optimally. From the research calculation the minimum reactance relay usage will work on XA-setting value zone (-2.55 p.u) with 0.5 seconds delay time, XB-setting (offset) of -0.1156 p.u with 0.5 seconds delay time. As for offset relay mho will work on zone 1 and zone 2 for offset value of -0.109 p.u with delay time 0.1 second. As for zone 1 for the base impedance ( ) of -1.0 p.u with a delay time of 0.1 seconds and zone 2 synchronous reactance value ( of 2.423 p.u with a delay time of 0.5 seconds. From those results it is considered sufficient to detect the loss of excitation in the synchronous generator.

scholarly journals Stability Assessment of Renewable Energy Integrated Power System

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3301-3307
Keyword(s):  
Power Generation ◽  
New England ◽  
Reactive Power ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Small Signal Stability ◽  
Synchronous Generators ◽  
Pv System ◽  
Negative Damping ◽  
Pv Generator

This paper investigates the small-signal stability of grid integrated Doubly Fed Induction Generator (DFIG) based Wind Turbine Generator (WTG) and Photovoltaic (PV) system. The short-circuit study is conducted for the New England 39-bus system using DIgSILENT PowerFactory software. The short-circuit study and dynamic simulation are performed for the study system with distributed generators. Furthermore, the eigenvalues are computed for the various damping level of synchronous generators. The influence of negative damping of synchronous machine with PV generator, DFIG based WTG in the study system is investigated. The eigenvalue analysis results shows that due to negative damping of synchronous generator the system become unstable even with PV generator and DFIG based WTG in the system. The time domain simulation results show that real power generation of the synchronous generator is decreased due to negative damping and its reactive power generation is increased.

Study on the Modes of Operation of a Multi-Machine Installations with Mechanical Reduction

2019 ◽  
pp. 12-22
Author(s):  
A. M. Oleynikov ◽  
L. N. Kanov
Keyword(s):  
Mathematical Description ◽  
Reactive Power ◽  
Maximum Efficiency ◽  
Wind Flow ◽  
System Of Equations ◽  
Mechanical Equilibrium ◽  
Synchronous Generators ◽  
Electromagnetic Excitation ◽  
Number Of Generators ◽  
Wide Range

The paper gives the description of the original wind electrical installation with mechanical reduction in which the output of vertical axis wind turbine with rather low rotation speed over multiplicator is distributed to a certain number of generators. The number of acting generators is determined by the output of actual operating wind stream at each moment. According to this constructive scheme, it is possible to provide effective and with maximum efficiency installation work in a wide range of wind speeds and under any schedule issued to the consumer of electricity. As there are no any experience in using such complexes, mathematical description of its main elements is given, namely windwheels, generators with electromagnetic excitation of magnetic electrical type, then their interaction with windwheel, and also the results of mathematical modeling of work system regimes under using the offered system of equations. The basis for the mathematical description of the main elements of the installation – synchronous generators – are the system of equations of electrical and mechanical equilibrium in relative units in rotating coordinates without considering saturation of the magnetic circuit. The equation of mechanical equilibrium systems includes torque and brake windwheel electromagnetic moments of generators with taking into account the reduction coefficients and friction. In addition, we specify the alternator rotor dynamics resulting from continuous torque of windwheel fluctuations under the influence of unsteady wind flow and wind speed serving as the original variable is modeled by a set of sinusoids. Model simplification is achieved by equivalization of similar generators and by disregarding these transitions with a small time constant. Calculation the installation with synchronous generators of two types of small and medium capacity taking into account the operational factors allowed us to demonstrate the logic of interactions in the main elements of the reported complex in the process of converting wind flow into the generated active and reactive power. We have shown the possibility of stable system work under changeable wind stream condition by regulating of the plant blade angle and with simultaneous varying of generator number of different types. All these are in great interest for project organizations and power producers.

scholarly journals Voltage Stability of Power Systems with Renewable-Energy Inverter-Based Generators: A Review

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 115
Author(s):  
Nasser Hosseinzadeh ◽  
Asma Aziz ◽  
Apel Mahmud ◽  
Ameen Gargoom ◽  
Mahbub Rabbani
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Voltage Stability ◽  
Reactive Power ◽  
Power Grid ◽  
Renewable Energy Sources ◽  
Electrical Power ◽  
System Stability ◽  
Special Issue ◽  
Synchronous Generators

The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids.

Operation Characteristics of Zone 3 Distance Protection in Wind Power Systems with Fixed-Speed Induction Generators

2011 ◽  
Vol 12 (4) ◽  
Author(s):  
Shenghu Li
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Reactive Power ◽  
Flow Analysis ◽  
Load Flow ◽  
Synchronous Generators ◽  
Induction Generators ◽  
Load Flow Analysis ◽  
Wind Power Systems ◽  
Operation Characteristics

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.

scholarly journals Analysis and Mitigation of Sub-Synchronous Resonance for Doubly Fed Induction Generator under VSG Control

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1582
Author(s):  
Yingzong Jiao ◽  
Feng Li ◽  
Hui Dai ◽  
Heng Nian
Keyword(s):  
Reactive Power ◽  
Synchronous Generator ◽  
Impedance Analysis ◽  
Damping Factor ◽  
Renewable Power ◽  
Induction Generators ◽  
Parameter Configuration ◽  
Impedance Modeling ◽  
Doubly Fed ◽  
Series Capacitor Compensation

This paper presents the analysis and mitigation of sub-synchronous resonance (SSR) for doubly fed induction generators (DFIG) under virtual synchronous generator (VSG) control, based on impedance methods. VSGs are considered to have grid-supporting ability and good stability in inductance-based weak grids, and are implemented in renewable power generations, including DFIG systems. However, stability analyses of VSGs for DFIG connecting with series capacitor compensation are absent. Therefore, this paper focuses on the analysis and mitigation of SSR for DFIG under VSG control. Impedance modeling of DFIG systems is used to analyze SSR stability. Based on impedance analysis, the influence of VSG control parameters and the configuration of damping factor of reactive power are discussed. Next, a parameter configuration method to mitigate SSR is proposed. Finally, time-domain simulation and fast fourier transform (FFT) results are given to validate the correctness and effectiveness of the impedance model and parameter configuration methods.

Adaptive SRF-PLL Based Voltage and Frequency Control of Hybrid Standalone WECS with PMSG-BESS

2018 ◽  
Vol 19 (6) ◽  
Author(s):  
Anjana Jain ◽  
R. Saravanakumar ◽  
S. Shankar ◽  
V. Vanitha
Keyword(s):  
Reactive Power ◽  
Frequency Control ◽  
Storage System ◽  
Synchronous Generator ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Operating Conditions ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Control Scheme

Abstract The variable-speed Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) attracts the maximum power from wind, but voltage-regulation and frequency-control of the system in standalone operation is a challenging task A modern-control-based-tracking of power from wind for its best utilization is proposed in this paper for standalone PMSG based hybrid-WECS comprising Battery Energy Storage System (BESS). An Adaptive Synchronous Reference Frame Phase-Locked-Loop (SRF-PLL) based control scheme for load side bi-directional voltage source converter (VSC) is presented for the system. MATLAB/Simulink model is developed for simulation study for the proposed system and the effectiveness of the controller for bi-directional-converter is discussed under different operating conditions: like variable wind-velocity, sudden load variation, and load unbalancing. Converter control scheme enhances the power smoothening, supply-load power-matching. Also it is able to regulate the active & reactive power from PMSG-BESS hybrid system with control of fluctuations in voltage & frequency with respect to varying operating conditions. Proposed controller successfully offers reactive-power-compensation, harmonics-reduction, and power-balancing. The proposed scheme is based on proportional & integral (PI) controller. Also system is experimentally validated in the laboratory-environment and results are presented here.

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