A Wavelet Based Differential Algorithm for Busbar Protection

Busbar protection is an essential component in power system design, protecting the most important system node for network stability and security. When faults occurs on busbar itself, it takes much time to isolate the bus from source which may cause much damage in the bus system. Faults in power system are classified as internal and external faults. Faults within the zone are termed as internal faults whereas, the faults outside the Zone are called as external faults. Ideally, a relay looking after the protection of a zone should operate only for internal faults. It should restrain from operating for external faults or through faults. In this paper the busbar protection using differential protection scheme has been investigated for internal and external faults. An algorithm has been developed to improve the selectivity of the relay and the same has been tested in IEEE9 bus system for internal and external faults. Separation of De-noised signal from fault signal is made using wavelet transform so that the nature of fault occurs on the system can be identified. In this study Daubechies 4 at level 3 is used to separate original signal and de-noised signal. The entire simulation has been done using MATLAB R2017a.

Download Full-text

Implementation of Differential Algorithm for Busbar Protection

International Research Journal of Multidisciplinary Technovation ◽

10.34256/irjmt19220 ◽

2019 ◽

pp. 150-157

Author(s):

Bharath Kumar Sugumar ◽

Sujatha Balaraman

Keyword(s):

Power Systems ◽

Circuit Breaker ◽

Current Transformer ◽

Differential Protection ◽

Protection Scheme ◽

Current Magnitude ◽

Three Phase ◽

Differential Algorithm ◽

Internal Faults ◽

External Faults

Faults in power systems are classified as internal and external faults. Faults within the zone are termed as internal faults whereas; the faults outside the Zone are called as external faults. Ideally, a relay outward after the protection of a zone should operate only for internal faults. It should restrain from operating for external faults or through faults. In this project, the busbar protection using differential protection scheme has been investigated for internal and external faults. The current magnitude from the Current Transformer is compared with a preset value and when the current exceeds the preset value, and then a trip command is given to associated circuit breaker. In this work, an algorithm has been developed to improve the selectivity of the relay and the same is tested on three-phase bus bar having two incoming lines and three outgoing lines at different fault levels and the results are verified for internal and external faults. The entire algorithm is programmed and graphical views of relay performance are verified using the MP LAB platform.

Download Full-text

A New Adaptive Differential Protection Scheme for Tap Changing Power Transformer

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2015-0005 ◽

2015 ◽

Vol 16 (4) ◽

pp. 339-348 ◽

Cited By ~ 2

Author(s):

Ashesh Mukeshbhai Shah ◽

Bhavesh Bhalja

Keyword(s):

Power Transformer ◽

Detection Sensitivity ◽

Power Transformers ◽

Test Cases ◽

Differential Protection ◽

Protection Scheme ◽

Differential Characteristic ◽

Numerous Test ◽

Internal Faults ◽

Conventional Scheme

Abstract This paper presents a new adaptive differential protection scheme which efficiently adapts the change in tap position of a power transformer. The proposed scheme is based on analytical derivation of pick-up and slope of the differential relay characteristic. By acquiring information such as rating & connection of CTs and present tap position as input, the proposed scheme enhances sensitivity of differential relay during internal faults. This is accomplished either by decreasing pick-up and/or adjusting slope of the differential characteristic of the relay in case of change in tap position. Numerous test cases consisting of various types of internal and external faults have been simulated for an existing power transformer of Gujarat Energy Transmission Corporation Limited (GETCO), Gujarat, India using PSCAD/EMTDC software package. The proposed scheme increases percentage of winding to be protected during internal faults for power transformers having different ratings and connections compared to the conventional differential protection scheme. Furthermore, it has been observed that the detection sensitivity during special types of turn-to-turn and inter-winding faults with varying fault resistances is also enhanced compared to the conventional scheme. Moreover, it equally maintains stability during CT saturation condition. At the end, comparative evaluation of the proposed scheme with the existing schemes clearly indicates superiority of the proposed adaptive scheme.

Download Full-text

Adaptive Differential Protection System for Microgrid

International Journal for Research in Applied Science and Engineering Technology ◽

10.22214/ijraset.2021.36880 ◽

2021 ◽

Vol 9 (VII) ◽

pp. 2364-2371

Author(s):

Rahul Kumar Bhardwaj

Keyword(s):

Power System ◽

Transmission Loss ◽

Green Energy ◽

Protection System ◽

Differential Protection ◽

Renewable Energy Resources ◽

Matlab Simulation ◽

Protection Scheme ◽

Simulation Based ◽

Electric Loads

Microgrids are the small version of power system which grants us the integration of distributed generation resources to insure the facilities to the remotely located electric loads as well as have so many advantages over traditional power system like reduced transmission loss, green energy solution and proper use of renewable energy resources. However the resilience offered by microgrid is inconvenient if it is not be able to protect properly in case of any disturbance occurs which is very common in microgrid due to load dynamics. Protective devices used in traditional power grid cannot actually protect microgrid due to variable loads and different fault levels at grid connected modes and islanded modes. The available research about this concern has not been very successful, therefore options like distance, directional over current and differential relay remains effective protection scheme from present standard. Even though these relays are very useful in power system but their effectiveness for microgrid is yet to be analyzed. This paper is presenting the MATLAB simulation based analysis for differential relay type adaptive protection system by taking a complex microgrid model and generating various fault and generation capacities and analyzing it. In this paper different scenarios has been discussed where differential relay seems to be better than distance and directional over current relay protection scheme.

Download Full-text