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

Author(s):  
Shenghu Li

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.

2019 ◽  
Vol 3 (1) ◽  
pp. 26 ◽  
Author(s):  
Vishnu Sidaarth Suresh

Load flow studies are carried out in order to find a steady state solution of a power system network. It is done to continuously monitor the system and decide upon future expansion of the system. The parameters of the system monitored are voltage magnitude, voltage angle, active and reactive power. This paper presents techniques used in order to obtain such parameters for a standard IEEE – 30 bus and IEEE-57 bus network and makes a comparison into the differences with regard to computational time and effectiveness of each solver


2005 ◽  
Vol 42 (4) ◽  
pp. 369-382 ◽  
Author(s):  
T. Yalcinoz

This paper presents a software package developed in Matlab for teaching power systems analysis and operation. The software package is used to support and enhance power engineering education at both undergraduate and postgraduate levels. The application programs in this package include fault analysis, load flow analysis, transient stability, economic dispatch, unit commitment and load forecasting. All modules of the package are independent of each other. The students or researchers can make copies of the software to study and can modify any module of the package.


2020 ◽  
Vol 12 (1) ◽  
pp. 70-83
Author(s):  
Shabbiruddin ◽  
Sandeep Chakravorty ◽  
Karma Sonam Sherpa ◽  
Amitava Ray

The selection of power sub-station location and distribution line routing in power systems is one of the important strategic decisions for both private and public sectors. In general, contradictory factors such as availability, and cost, affects the appropriate selection which adheres to vague and inexact data. The work presented in this research deals with the development of models and techniques for planning and operation of power distribution system. The work comprises a wider framework from the siting of a sub-station to load flow analysis. Work done also shows the application of quantum- geographic information system (Q-GIS) in finding load point coordinates and existing sub-station locations. The proposed integrated approach provides realistic and reliable results, and facilitates decision makers to handle multiple contradictory decision perspectives. To accredit the proposed model, it is implemented for power distribution planning in Bihar which consists of 9 divisions. A Cubic Spline Function-based load flow analysis method is developed to validate the proposal.


Author(s):  
Tapash Das ◽  
Jingxin Zhang ◽  
Hemanshu Pota

AbstractWind power is a major contributor in the renewable energy sector but it faces some issues regarding modern grid-code compliance. Popular wind power systems based on Doubly-Fed Induction Generators (DFIG) need additional protection under grid voltage disturbances. They also need to support the grid voltage under such transient occurrences. This paper presents a novel performance enhancement scheme for DFIGs subjected to symmetrical and asymmetrical voltage sags and swells at the Point of Common Coupling (PCC). The scheme comprises a protection system and a reactive power management system working simultaneously under the command of a supervisory control system. The protection system protects the DFIG converter by limiting the overcurrent in the Rotor Side Converter (RSC) of the DFIG and keeping the dc-link capacitor voltage within an acceptable range; whereas, the reactive power management supports the grid voltage by either injecting or absorbing reactive power to reduce the magnitude of voltage sags and swells. It is found that the performance of the DFIG wind generation system improves significantly under the proposed scheme. A grid-connected 9-MW DFIG wind farm is used for simulation in MATLAB/Simscape Power Systems.


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