scholarly journals Implementation of Differential Algorithm for Busbar Protection

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.

A Wavelet Based Differential Algorithm for Busbar Protection

2019 ◽  
Vol 1 (3) ◽  
pp. 28-39
Author(s):  
Bharath Kumar Sugumar ◽  
Sujatha Balaraman
Keyword(s):  
Power System ◽  
Differential Protection ◽  
Network Stability ◽  
Protection Scheme ◽  
Level 3 ◽  
System Node ◽  
Internal Faults ◽  
Important System ◽  
Bus System ◽  
External Faults

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.

A New Adaptive Differential Protection Scheme for Tap Changing Power Transformer

2015 ◽  
Vol 16 (4) ◽  
pp. 339-348 ◽  
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.

A Novel Approach for Classifying Transient Phenomena in Power Transformers

2004 ◽  
Vol 1 (2) ◽  
Author(s):  
El Sayed M. Tag Eldin
Keyword(s):  
Fuzzy Logic ◽  
Wavelet Transforms ◽  
Power Transformer ◽  
Current Transformer ◽  
Transient Phenomena ◽  
Protective Relay ◽  
Novel Approach ◽  
Inrush Currents ◽  
Internal Faults ◽  
External Faults

The role of a power transformer protective relay is to rapidly operate the tripping during internal faults and block the tripping during magnetizing inrush. This paper presents a new approach for classifying transient phenomena in power transformer, which may be implemented in digital relaying for transformer differential protection. Discrimination between internal faults, external faults with current transformer saturation and magnetizing inrush currents is achieved by combining wavelet transforms and fuzzy logic. The wavelet transform is applied for the analysis of the power transformer transient phenomena because of its ability to extract information from the transient signals in both time and frequency domain. Fuzzy logic is used because of the uncertainty in the differential current signals and relay settings. MATLAB power system toolbox is used to generate current signals at both sides of a power transformer in a typical system with various conditions. The simulation results obtained show that the new algorithm provides a high operating sensitivity for internal faults and remains stable for external faults and inrush currents.

scholarly journals Differential Protection of Power Transformer using Wavelet Transform

2019 ◽  
Vol 8 (3) ◽  
pp. 7627-7630
Keyword(s):  
Wavelet Transform ◽  
Power Transformer ◽  
Circuit Breaker ◽  
Inrush Current ◽  
Differential Protection ◽  
Time Duration ◽  
Transform Method ◽  
Protection Scheme ◽  
Magnetizing Inrush Current ◽  
Clearing Time

This paper presents wavelet transform method for the analysis of differential currents of power transformer which can act as an accurate classifier between magnetizing inrush current and internal faults to avoid the needless tripping of circuit breaker. The differential protection scheme occasionally mal – operate whenever magnetizing inrush occurs in power transformer. The aim is to reduce the rate and time duration of undesired outages of power transformer. This includes the necessities of reliability with zero mal – operation of differential relay. The result shows higher operating speed with less fault clearing time. Wavelet Transform is employed for the analysis of transient signals under various conditions, which extracts data from signals in time and frequency domain simultaneously. The simulation is done in MATLAB environment.

Analysis on 2nd Main Transformer Trip Accident of a Certain Substation of the West Inner Mongolia Power Grid

2012 ◽  
Vol 516-517 ◽  
pp. 1312-1315
Author(s):  
Li Juan Ge ◽  
Yong Zhang ◽  
Haijun Li
Keyword(s):  
Sampling Error ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Current Transformer ◽  
Differential Protection ◽  
Prevention Measures ◽  
Action Mechanism ◽  
The West ◽  
Protection Circuit

This paper mainly analyzes the causes of a 10KV line and 2nd transformer circuit breaker tripping, also analyzes the action mechanism of the relay protection. Because of the permanent phase fault at the head of the line, instantaneous over-current protection(SegmentⅠ) as its main protection of the phase fault made the 921 breaker triping, the action was selective.And the permanence of this fault led to the failure of the reclosing; Reversed the TA(current transformer) for measuring with the TA for differential protection in high voltage side of the transformer, this fault can also make the TA of the differential protection circuit quickly saturated when the external short-circuit current flowing through the TA. When the above saturation happens, a big differential current generating from differential circuit will lead to sampling error. This is the direct cause of the mal-operation of the differential protection which resulting in the 2nd transformer tripping. In response to this accident, put forward specific prevention measures.

Sign in / Sign up

Export Citation Format

Share Document