Insights into testing and validation of DC offset removal filters in numerical distance protection
01 Dec 2012-pp 075-080
TL;DR: In this paper, the authors provide insights into testing and validating DC offset removal filters, which are not focused till now, and this is done by comparing the performance of three dc offset removal filter, digital mimic filter (DMf), patented filter (pf), and double differentiator filter (ddf).
Abstract: Distance relay maloperates due to various reasons, like dc offset in current waveforms, capacitive voltage transformer transients, remote-end in-feed in the presence of fault resistance, power swings and loading. dc offset in current waveforms results in overreach, causing distance relay to operate for faults outside its protected zone. There are many offset removal filters proposed by researchers in literature, but it is found, that the same ideas fail to penetrate as a filter into today's Intelligent Electronic Devices (IED). The objective of this paper is not to propose a new filter, but to provide insights into testing and validating those DC offset removal filters, which are not focused till now. This paper provides the additional factor to be considered for validating filters, which are proposed for dc offset removal and this is done by comparing the performance of three dc offset removal filters, digital mimic filter (dmf), patented filter (pf) to remove dc offset and double differentiator filter (ddf) which are currently used by relay manufacturers.
Citations
More filters
01 Nov 2013
TL;DR: An IEC 61850 based laboratory prototype is developed using royalty free and free and open source software (FOSS) for modeling the power system and the distance relay and a complex and vital protection scheme known as local breaker backup (LBB) which has been recently integrated into a centralized bus bar protection scheme is implemented and tested.
Abstract: With the increasing adoption and implementation of IEC 61850 based substation automation systems (SAS), it has now become very important for power system engineers to know and understand technologies outside the realm of regular power system concepts which are not taught until graduate studies. Present day tools and systems are either costly and proprietary in nature or, are open source but not easy to understand and use them to implement and test protection and automation schemes based on International Electro technical Commission (IEC) 61850 in a lab based environment. Taking this as motivation, an IEC 61850 based laboratory prototype is developed using royalty free and free and open source software (FOSS) for modeling the power system and the distance relay. In order to show the flexibility of the proposed framework, a complex and vital protection scheme known as local breaker backup (LBB) which has been recently integrated into a centralized bus bar protection scheme is implemented and tested. Personal computers are used as merging unit (MU) and intelligent electronic devices (IEDs), and, Ethernet based local area network (LAN) and switches have been used for implementing process bus and station bus. This cost effective prototype can be used by the academia and engineers to study, understand, implement and test various IEC 61850 based protection and automation schemes.
2 citations
References
More filters
Book•
01 Jan 1999
TL;DR: This paper describes the design and operation of a mobile phone system and some of the techniques used in its manufacture and maintenance, as well as some of its applications.
Abstract: 1. Introduction. 2. Definitions. 3. Mode of Operation. 4. Device Design. 5. Application. 6. Protection Settings. 7. Calculation Examples. 8. Commissioning. 9. Maintenance. 10. Bibliography. 11. Appendix. Index.
321 citations
"Insights into testing and validatio..." refers background in this paper
...The reason being, in the former case Rf can cause overreaching and underreaching effect in the presence of remote-end in-feed [7] and in the latter case, transients in the first post fault cycle causes overreaching effect [8]....
[...]
TL;DR: In this paper, the capability of popular digital filters used in relaying applications to suppress DC offset in current waveforms over a broad range of time constants as encountered on real power systems was investigated.
Abstract: This paper presents a theoretical investigation of the capability of popular digital filters used in relaying applications to suppress DC offset in current waveforms over a broad range of time constants as encountered on real power systems. First, three mathematical performance indices are introduced to be able to compare filters on the same basis. Then the concept of the FIR type of digital mimic filter is described. It is shown that, for filters exhibiting a null response at frequency zero on their frequency response, the addition of a digital mimic circuit, tuned to the middle of the range of time constants to be suppressed, will almost completely eliminate the effect of an exponentially decaying component. Moreover, this is possible without sacrificing the original response speed, although it increases susceptibility to noisy components. >
296 citations
"Insights into testing and validatio..." refers background in this paper
...Digital mimic filter The design of this filter will not be done here, since the mathematical basis is well documented in [4]....
[...]
...the performance index (PI2) proposed in [4] is included here....
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Book•
01 Jan 1985
79 citations
"Insights into testing and validatio..." refers background in this paper
...Trip signal is asserted when the estimated positive sequence impedance lies within the mho characteristic, which is detected by angle criteria [1]....
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Book•
11 Dec 2004
TL;DR: This book provides both the underpinning knowledge and basic calculations needed to understand, specify, use and maintain power protection systems, and the practical techniques required on a daily basis.
Abstract: lant operators, electricians, field technicians and engineers will gain a practical understanding of the role and workings of power system protection systems from this work. An understanding of power systems and their optimized management will increase plant efficiency and performance as well as increasing safety levels. This book provides both the underpinning knowledge and basic calculations needed to understand, specify, use and maintain power protection systems, and the practical techniques required on a daily basis.After studying this book you will have an excellent knowledge of the principles of protection. You will also have a better understanding of the possible problems likely to arise in day-to-day work with power protection systems.Key areas of knowledge and expertise developed will include:
Fundamentals of electrical power protection and applications
Different fault types
Perform simple fault and design calculations
Practical knowledge of protection system components
Apply relay settings
Improve the safety of your site with the knowledge gained
63 citations
"Insights into testing and validatio..." refers background in this paper
...This is one of the main requirement for any protective relay [2] which is not considered for validating filters, which are proposed to remove dc offset....
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Patent•
18 Aug 1993
TL;DR: In this paper, a sub-cycle digital distance relay which uses only the first N/2 samples after a fault to calculate the distance to the fault using a Full Cycle Fourier Algorithm was proposed.
Abstract: A sub-cycle digital distance relay which uses only the first N/2 samples after a fault to calculate the distance to the fault using a Full Cycle Fourier Algorithm which operates on N samples, where N is the number of samples taken in a cycle of the power signal. The DC offset in the first N/2 samples taken after detection of the fault is cancelled using the N/2+1 sample taken after detection of the fault. The resulting DC adjusted N/2 samples are then multiplied by -1 in order to take advantage of the symmetry of the sine wave of the power signal in estimating the remaining N/2 samples of the first cycle of the power signal after detection of the fault. By so calculating N/2 artificial samples from the first N/2 actual samples taken after the fault, the digital distance relay of the invention can estimate the distance to the fault and thus provide a reliable trip signal in less than one cycle of the power signal. The technique of the invention is used to implement a high-speed tripping mode for use in conjunction with conventional tripping schemes to provide a more reliable tripping signal in a minimum amount of time after the detection of the fault, thereby providing improved fault protection for the power transmission components.
57 citations