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Numerical phase comparison protection overcomes the problems faced on the long EHV transmission system by providing dynamic compensation of charging current at all times thus providing stability during external fault conditions. With the implementation of impedance starters complimenting current and voltage starters, enhances the sensitivity thus enabling the gap detection algorithm, which is based...
Standard communication protocols have been used for substation automation for many years. The applications are mainly on the station level communication to indicate alarms and events within a substation and make them visible to the operator. However the configuration and implementation of the protocols have differed widely between manufacturers leading to difficulties when attempting to support product...
Operational Telecommunications (OpTel) play a vital role in the safe, reliable and efficient operation of a power distribution network. Over the time, different OpTel services and technologies have developed around individual power system applications. This has resulted in the creation of isolated islands of telecommunication technologies. The technologies associated with telecommunication services,...
As busbar is one of the most important power system nodes, the busbar protection is an essential component in network design, considering the power system stability and security. So busbar protection should fulfill the requirements of fast operating times for all kinds of busbar faults, security for external faults with heavy current-transformer (CT) saturation, and minimum delay for evolving faults...
In radial distribution systems, three step current protection, also called overcurrent protection, has been widely used for many years. When distributed generators (DGs) are connected to a radial distribution system, they will have some effects on the traditional overcurrent protection scheme and may lead to false tripping. This paper proposed a new communication supported fast current protection...
This paper investigates the use of wide area measurements to estimate the damping of power system oscillations. At present, most damping estimation methods use a single measurement. Two test systems are simulated and a subspace identification method is used to demonstrate that having multiple measurements can improve the estimate.
Shunt reactors are installed on long lines (in this case a 435km 765kV line) to reduce over voltages experienced when the load is suddenly lost and to control voltages under lightly loaded conditions. When the compensated line is opened to clear a fault, it is found that the open-phase voltage does not disappear. A transient voltage waveform with a resonant frequency between 35Hz and 45Hz can be seen...
Conventional overload protective devices for induction motors like thermal, induction type, static and digital protection require motor current/s as the common parameter to be sensed accurately for reliable operation of the relay. The paper reports development of a novel overload cum short circuit protection relay for three phase induction motors without requiring motor current as its input parameter...
For the Delayed Auto-Reclose (DAR) and Autoswitching (ASW) systems in Mesh Corner circuits, taking into consideration the desire to minimise the overall system cost by reducing hardwired connections and auxiliary relays, the advanced multifunctional numerical relays with GOOSE (Generic Object Oriented Sub-Station Event) Communication interface via UCA2 (Utility Communication Architecture) protocol...
The paper analyses the existed protection of microgrid. And in order to meet the requirements of microgrid protection, a novel protection is presented in this paper. The protection based on local information without the need of communication, uses current traveling waves to identify faulted feeder, and the bus bar voltages to determine a event caused by fault or switch operation. In the protection...
A new approach using transient signals for earth fault location in non-solidly earthed overhead lines is presented. The characteristics of zero module network are analyzed in detail. Also, the product of zero-module voltage after Hilbert transform and zero-module current in selected frequency band is determined the direction of the fault. The earth fault can be located in accordance with the difference...
This paper developes a fault diagnosis system based on IEC61970 and IEC61850 standard series. The key problems in fault diagnosis system are the deficiency and standardization of distributed fault information. This fault diagnosis system get fault information mainly from SCADA and fault information system. The information from SCADA, including network topology and switch state, is modeled based on...
Phasor measurement units are power system devices that provide synchronized measurements of real-time phasors of voltages and currents. The aim of this paper is to provide comprehensive survey on optimum phasor measurement unit (PMU) for power system placement .The different Algorithm used for the optimum PMU placement is discussed in detail.
The Cost-effective solutions to improve system planning, operation, maintenance, and energy trading are achieved through wide area monitoring protection and control (WAMPAC). The most accurate and advanced timesynchronized technology available to power engineers and system operators for WAMPAC applications are phasor measurement units. This paper presents a comprehensive review on application of WAMPAC...
The integration of distributed generation transforms current distribution networks from vertically operated to horizontally operated. This transition leads to problems related to protection coordination. In the future, new protection philosophies should be applied which guarantee the increase of the during-fault distributed generation availability. The paper presents a protection scheme based on fault...
The authors suggest the concepts of protection relay systems for operation within a Smart Grid and describe the results of a prototype development. This paper introduces each of the system characteristics that should be considered for protection operation within Smart Grid, and the evaluation methods that were applied under both normal and faulted conditions. The results of a field trial in the 66kV...
Wind generation and wind farms are becoming an important part of the generating capacity of the modern utility grid. Protection of wind turbines, and wind farm collector systems, has been the subject of numerous technical papers over recent years, as wind generation grows more prevalent. These papers have focused on the basics of protecting the wind turbines, protecting the wind farm, and modelling...
The Architecture of Substation Secondary Systems (AS3) [6] is a project within National Grid Electricity Transmission which is seeking to overcome some of the ownership challenges presented by modern protection and control (P&C) devices, which have an inherent short life due to their dependence on modern electronics and software. This will be achieved by implementation of a process bus using IEC...
This work presents a new approach for a current differential protection of the transmission lines. The proposed approach is based on the Clarke-Concordia transformation and principal component analysis. First the acquired current signals are transformed into “αβo” components by applying the Clarke-Concordia transformation. This allows obtaining typical patterns. To identify these patterns a principal...
The transient transmission error of Capacitor Voltage Transformer (CVT) may cause the incorrect action of relay protection. A Novel correcting method for transient error of CVT is proposed. Using this method, CVT's primary side voltage can be calculated accurately with the secondary side voltage known. The node voltage equations based on integral equivalence is used to simplify the computation of...
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