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Surge Impedance Relay(SIR) is applied to DC system. Characteristics of SIR in DC line are analysed. A DC SIR algorithm implementing wavelet transform applied to HVDC line protection is proposed. The feasibility of DC SIR is verified and the performance of DC SIR is simulated and analysed.
The selection of the faulty feeder in the case of single phase-to-earth fault in a Neutral Un-effectively Grounded System (NUGS) has been one of the conventional problems of distribution network. The compensation method is introduced to highlight the difference of the zero-sequence admittances between the faulted feeder and the sound feeder. In this way, the setting of the criterion becomes feasible...
Energy supply is a significant resource for economic and social development. Statistics show that the lightning phenomenon is one of the most important causes of power systems outage. On this context, the development of novel methodologies for the analysis and study of distribution feeder performance against direct and induced lightning has continually been imperative and wanted for researchers, utilities...
This paper presents an accurate fault location algorithm for a double-circuit transmission line with series capacitor compensation at its both ends. Use of one-end measurements: three-phase voltage and three-phase currents from both line circuits has been considered. The algorithm is formulated m phase co-ordinates. The developed algorithm has been tested and evaluated using signals taken from ATP-EMTP...
The location procedure of HIF is a very difficult task and represents a great challenge for distance protection of transmission lines due to the under-reach and overreach effects. A new contribution for high impedance fault location for short transmission lines is proposed in this paper. The basic idea consists in solving an overestimated system using the method of the least square to locate the fault...
As the single-ended traveling-wave fault location method is cost effective and no need for synchronization device, it has been widely researched and discussed. However, the major problem is the identification of the reflected wave-head caused by the fault point. The reflected surge from the adjacent bus usually has the same polarity as the real fault point's reflected wave-head, so a confusion is...
The distribution network detection devices are generally using two kinds of instrument current transformer (ICT), of which one is used to transform the travelling wave and transient signals, while the other is used to transform the power frequency signals. Such scheme is neither necessary nor economical. This paper analyses the influences of sampling resistance, stray capacitance and magnetizing inductance...
Major power system disturbances and outages have a significant economic and social impact and the security of supply becomes a more and more important issue. Hence outage times should be as short as possible. Smart grid technologies such as self-healing networks can help in reducing the outage times after a disturbance. In this paper the principle and implementation of a self-healing grid based on...
This paper presents UK Power Networks' approach to protecting the first 33kV Quadrature-booster deployed on a distribution network including its integration with the existing protections schemes in the surrounding network. The paper will also briefly cover the control and operational considerations to effectively manage an identified network constraint using the Quadrature-booster.
This paper will present differential protection schemes used for special Converter Transformers. These transformers are typically used to feed MV drives, power electronic or FACTS devises. Converter transformers are industrial power transformers which may have phase angle shift different from standard 30º or a multiple of 30º. Typical example is 24-pulse converter transformer with additional phase...
In this paper the problems of protecting a cross-bonded cable system using distance protection are analysed. The combination of the desire to expand the high voltage transmission grid and the public's opinion towards new installations of overhead lines (OHL), more and more transmission cable systems are being laid around the world. Differential protection is often used for the main protection of cables...
PRP (Parallel Redundancy Protocol) is one of the methods that can be applied to implement Ethernet network redundancy. PRP is defined in Part 3 of the IEC 62439 Standard [1]. The paper discusses the principle of operation of PRP, and the benefits for use in an IEC 61850-based Substation Automation System, compared with some other redundancy protocols. One of the main benefits of PRP to users is that,...
The "Energy Turnaround" is not a vision anymore — it is reality. With an analysis of blackouts and important disturbances in Europe since 2003 this paper describes the sequence of events and challenges restoring the grid. Since in most of the disturbances described renewables have been involved the paper describes concrete problems and impacts on protection and control. After every blackout...
This paper presents a system developed for on-line evaluation and verification of protection relay settings based on the advanced information and computer technology. The inputs to the system are real-time topology and operation data of electricity networks from the EMS, and protection settings obtained from relays. The relay settings are evaluated by simulating various faults on the real-time topology...
The analysis and interpretation of the quality of a nationwide protection system is challenging. This paper presents a new method for an automated analysis of the protection system of electrical energy systems. The intent was to find a fast and holistic approach. The holistic requirement is fulfilled by analysing all relays locally and in dependency to the surrounding ones, whereas more than just...
In this paper, a transient stability real-time detection scheme based on the WAMS information is proposed for the multi-machine system. The relation between trajectory convexity and the Single Machine Infinite Bus (SMIB) system instability is demonstrated mathematically and graphically in the beginning. Based on the relation a simple and easy calculated instability criterion is proposed for the ideal...
In the long-distance and extra high voltage transmission system, distance protection has been widely used. Distance protection needs to determine if a fault is internal or external to a protection zone by calculating fault distance between the relay and the fault point. In another word, quickly and accurately extracting power-frequency phasor from transient fault signals is one of the most crucial...
In this paper, a novel wide area measurement system (WAMS) based distance protection scheme for parallel transmission lines is proposed. This protection scheme sufficiently utilizes the information in WAMS to set up an accurate system model in remote terminal. Then the proposed scheme uncouples the model into a six-sequence mathematical model to eliminate the influence of the zero-sequence mutual...
This paper aims to look closely at the role of directional overcurrent (DOC) protection and investigate options for modifying the existing schemes or settings in the context of reverse power flow constraints for accommodating distributed generation in distribution networks. It will also consider alternative solutions and assess their suitability and impact from a technical perspective. The paper will...
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