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.

scholarly journals Minimum Short Circuit Ratio Requirement for MMC-HVDC Systems Based on Small-Signal Stability Analysis

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3283 ◽  
Author(s):  
Zheren Zhang ◽  
Liang Xiao ◽  
Guoteng Wang ◽  
Jian Yang ◽  
Zheng Xu
Keyword(s):  
Reactive Power ◽  
Short Circuit ◽  
Small Signal ◽  
Small Signal Stability ◽  
Ratio Requirement ◽  
Planning Stage ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Signal Stability

This paper determines the minimum short circuit ratio (SCR) requirement for a modular multilevel converter based high-voltage direct current (MMC-HVDC) transmission systems. Firstly, a simplified model of MMC is introduced; the MMC is represented by its AC and DC side equivalent circuit. Next, by linearizing the MMC subsystem and the DC network subsystem, the deduction of the small-signal models of MMC subsystem, the small-signal model of the DC network and MMC-HVDC are carried out successively. Thirdly, the procedure for determining the minimum SCR requirement of MMC-HVDC is described. Finally, case studies are performed on a two-terminal MMC-HVDC system under four typical control schemes. The results show that the restraint factors for the rectifier MMC is predominantly the voltage safety limit constraint, and the restraint factors for the inverter MMC are mainly the phase locked loop (PLL) or the outer reactive power controller. It is suggested that the minimum SCR requirement for the sending and the receiving systems should be 2.0 and 1.5 in the planning stage.

Short-Circuit Model and Simulation Characteristics of Synchronous Generators

2012 ◽  
Vol 241-244 ◽  
pp. 709-716
Author(s):  
Wan Qing Song ◽  
Qi Zhong Liu ◽  
Xu Dong Teng ◽  
Chao Gang Yu
Keyword(s):  
Theoretical Analysis ◽  
Simulation Model ◽  
Short Circuit ◽  
Influence Factors ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Model And Simulation ◽  
Simulation Results ◽  
Physical Quantities ◽  
Tremendous Impact

In this paper, the electrical transient mode of synchronous generators is studied, four different simulation model of synchronous generator on sudden short circuit was built, various physical quantities were studied by simulation during the short circuit. By comparing theoretics with simulation, various physical quantities of synchronous generator produced tremendous impact and surge during the sudden circuit and they stabilized in the proceeding state of short circuit. Thoroughly simulation analyzed, the results of simulation are identical with theoretical analysis. The simulation results show that these influence factors should be considered when we design the relay protections.

scholarly journals Adaptive Armature Resistance Control of Virtual Synchronous Generators to Improve Power System Transient Stability

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2365
Author(s):  
Daniel Carletti ◽  
Arthur Eduardo Alves Amorim ◽  
Thiago Silva Amorim ◽  
Domingos Sávio Lyrio Simonetti ◽  
Jussara Farias Fardin ◽  
...  
Keyword(s):  
Adaptive Control ◽  
Power System ◽  
Transient Stability ◽  
Short Circuit ◽  
Stability Margin ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Resistance Change ◽  
Clearing Time ◽  
Fault Current Limiters

The growing number of renewable energy plants connected to the power system through static converters have been pushing the development of new strategies to ensure transient stability of these systems. The virtual synchronous generator (VSG) emerged as a way to contribute to the system stabilization by emulating the behavior of traditional synchronous machines in the power converters operation. This paper proposes a modification in the VSG implementation to improve its contribution to the power system transient stability. The proposal is based on the virtualization of the resistive superconducting fault current limiters’ (SFCL) behavior through an adaptive control that performs the VSG armature resistance change in short-circuit situations. A theoretical analysis of the problem is done based on the equal-area criterion, simulation results are obtained using PSCAD, and experimental results are obtained in a Hardware-In-the-Loop (HIL) test bench to corroborate the proposal. Results show an increase in the system transient stability margin, with an increase in the fault critical clearing time (CCT) for all virtual resistance values added by the adaptive control to the VSG operation during the short-circuit.

scholarly journals Grid-connected Response Verification of AC Microgrid under Single Line-to-ground Short Circuit

2019 ◽  
pp. 1-10
Author(s):  
Maruf A. Aminu
Keyword(s):  
Power Systems ◽  
Reactive Power ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Dynamic Responses ◽  
Single Line ◽  
Physical Systems ◽  
Short Circuits ◽  
Power System Performance ◽  
Grid Interconnection

In design of power systems, assumptions are made to model the physical systems. The assumptions may not sufficiently reflect the behavior of the system under normal and faulted conditions. Under short circuit conditions, system parameters vary significantly, particularly in microgrids with grid interconnection capabilities. This paper presents the result of validating the response of a microgrid which is capable of grid interconnection and islanding under voltage and reactive power control regimes. The microgrid is modeled to incorporate two wind turbines, each rated 5.5 kW, 400 V. The utility has synchronous generator rated 100 MW, 13.8 kV. Both the utility and microgrid are capable of exchanging active power and reactive power. Single line-to-ground short circuits are introduced and withdrawn at 30.00 s and 32.00 s, respectively. The dynamic responses of the testbed are captured pre-, during- and post-short circuit in grid-connected mode under both control regimes. The response of the testbed is verified to be consistent with established short circuit theory, verifying the validity of the system for short circuit detection and analysis. The testbed can therefore be used for short circuit and related studies, design optimization and power system performance prediction.

scholarly journals The Short-Circuit Protections in Hybrid Systems with Low-Power Synchronous Generators

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 160
Author(s):  
Bartosz Rozegnał ◽  
Paweł Albrechtowicz ◽  
Dominik Mamcarz ◽  
Natalia Radwan-Pragłowska ◽  
Artur Cebula
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Electrical Systems ◽  
Protection Devices ◽  
Short Circuits ◽  
Damage Type

Single-phase short-circuits are most often faults in electrical systems. The analysis of this damage type is taken for backup power supply systems, from small power synchronous generators. For these hybrid installations, there is a need for standard protection devices, such as fuses or miniature circuit breaker (MCB) analysis. Experimental research mentioned that a typical protective apparatus in low-voltage installations, working correctly during supplying from the grid, does not guarantee fast off-switching, while short-circuits occur during supplication from the backup generator set. The analysis of single-phase short-circuits is executed both for current waveform character (including sub-transient and transient states) and the carried energy, to show the problems with the fuses and MCB usage, to protect circuits in installations fed in a hybrid way (from the grid and synchronous generator set).

scholarly journals ANALYSIS OF OVERVOLTAGE POSSIBILITY ON THE EXCITATION WINDING OF A SYNCHRONOUS GENERATOR OF AUTONOMOUS POWER SUPPLY SYSTEM IN CASE OF EXTERNAL SYMMETRICAL SHORT CIRCUIT

2021 ◽  
pp. 112-115
Author(s):  
V.B. Beliy ◽  
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Short Circuit ◽  
Electric Energy ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Excitation System ◽  
Three Phase ◽  
Short Circuits ◽  
Analytical Expressions

Reliable supply of consumers with electric energy largely depends on the reliability of power source function-ing. In the context of this paper it depends on synchronous generators operating in autonomous power supply sys-tems. In contrast to the power plant generators which are part of power systems and are protected from the loads by sufficiently large resistances, power supply systems withautonomous generators are characterized by rather low resistances. Abrupt changes in the supply load parameters, their own transient and emergency modes, for example, short circuits at the generator terminals, forcing excitation, etc. may lead to various failures in the synchronous gener-ator operation. This paper discusses the possibility of over-voltage in the valve excitation system of a synchronous generator with external three-phase short circuits. On the basis of analytical expressions describing the physical pro-cesses occurring in the excitation system of synchronous generators, the conditions for the occurrence of overvolt-ages are identified

scholarly journals Performance of Multifunctional Smart PV-Based Domestic Distributed Generator in Dual-Mode Operation

Machines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 356
Author(s):  
Kumar Chandrasekaran ◽  
Jasper John Sahayam ◽  
Sundarsingh Jebaseelan Somasundaram David Thanasingh ◽  
Sripriya Ramalingam ◽  
Hady H. Fayek ◽  
...  
Keyword(s):  
Reactive Power ◽  
Control Structure ◽  
Complex Structure ◽  
Synchronous Generator ◽  
Current Control ◽  
Operating Conditions ◽  
Pv System ◽  
Distributed Generator ◽  
Islanded Mode ◽  
Single Phase Inverter

This article briefs about a smart multifunctional single-phase inverter control for a domestic solar photo voltaic (PV)-based distributed generation that can work in both a grid-connected mode and an islanded mode by making the inverter mimic the operation of a synchronous generator. The control objectives were threefold: to provide the required active and reactive power for normal operating conditions and under varying operating conditions, to maintain the rated voltage and the rated frequency for the islanded mode, and to switch between the two modes of operation with the least amount of disturbance for the system while behaving as a virtual synchronous generator (VSG). The control structure is divided into three major loops: the outermost loop responsible for power control, the middle loop responsible for voltage control, and the innermost loop responsible for current control. The proposed control methodology incorporates the functionalities of the grid-connected and the islanded-mode control into a single complex structure and thus provides support to the grid under abnormal conditions while providing good-quality power to consumers under grid failure. The efficacy of the system is good. The operation under various modes were simulated in MATLAB Simulink, and the proportional integral (PI) controllers used for current controllers were tuned using particle swarm optimization (PSO). It can be concluded that the control structure becoming complex is benefitted by the added advantages of the smart PV system. The smart domestic PV system helps the prosumer to actively provide frequency support and voltage support, adding frequency support to the existing multifunctional PV systems.

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>

scholarly journals Multistep Finite Control Set Model Predictive Control of Photovoltaic Power Generation System with Harmonic Compensation

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xuejiao Gong ◽  
Shifeng Hu ◽  
Ruijin Zhu
Keyword(s):  
Power Generation ◽  
Reactive Power ◽  
Power Grid ◽  
Dynamic Performance ◽  
Maximum Power ◽  
Pv System ◽  
Nonlinear Load ◽  
Harmonic Compensation ◽  
Power Point ◽  
Pv Power Generation

Photovoltaic (PV) power generation is the main aspect of new energy power generation, and it is an important means to achieve the goal of carbon neutrality. When the PV system is connected to the grid, the nonlinear load of the grid will affect the power quality and consume reactive power. This paper proposes a PV power generation grid-connected system to improve power quality, with an active power filter (APF) function. Through the maximum power point tracking (MPPT) method, PV power generation can operate at the maximum power point and play the function of harmonic and reactive power compensation at the load side. To improve the dynamic performance of the grid-connected PV system and harmonic compensation simultaneously, multistep finite control set model predictive control (FCS-MPC) is adopted for the grid-connected module. The whole system does not need additional equipment, as it plays the role of two devices and effectively reduces the input cost. In this paper, the proposed structure and multistep FCS-MPC are verified in MATLAB/Simulink. The results show that the system injects the maximum power into the power grid at the same time when the load changes and compensates the harmonic generated by the nonlinear load of the power grid so that the total harmonic distortion of the power grid can meet the operation standard, and the system has good dynamic performance and steady-state performance.

scholarly journals STUDY OF ELECTROMECHANICAL COMPLEXES WITH SYNCHRONOUS GENERATORS WITH DIFFERENT SYNCHRONIZATION MODES

2018 ◽  
Vol 1 (12) ◽  
pp. 54-57
Author(s):  
Yuriy Konovalov ◽  
Stepan Sadovskiy ◽  
Maksim Krivosheev ◽  
Angelina Tihonova
Keyword(s):  
Short Circuit ◽  
Experimental Studies ◽  
Synchronous Generator ◽  
Parallel Operation ◽  
Synchronous Generators

The results of experimental studies of various methods of synchronization of electromechanical complexes with synchronous generators arising when the synchronous generator is turned on for parallel operation with the network and during self-synchronization during emergency modes of a short circuit are presented.

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