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This paper describes how increased functionality of the Network Rail Integrated Protection and Control (IPC) extended IEC 61850 station bus solution unlocks the ability to rationalise the electrification system design, and hence achieve a substantial reduction in primary plant requirements when delivering the new railway electrification schemes committed by the Government.
The large AC generators in a power plant are core facilities for providing stable production and supply of electric power in many applications. The generator protection system has very important role in maintaining stability in a power system. The generator protection systems in South Korea have been imported and operated through a turn-key from overseas entirely. Recently, with increase in the power...
Application of local data at receiving node of the system to estimate and control its parameters were considered in the paper. Using Thevenin model some methods were developed, analysed and simulated allowing to estimate and control stability margin and voltage level. The results can be used to construct voltage controller on basis of power electronics.
Phasor Measurement Units (PMUs) have the potential to play an essential role in power system monitoring and operation in the future, particularly for power systems incorporating increasing amounts of distributed generation (DG) and possibly systems operating in islanded mode in the future [1]. Their ability to directly measure and provide the voltage and current phasors at the PMU location offers...
Modern microprocessor-based low-impedance differential relays use a percentage differential principle that utilizes traditional dual slope characteristics. Many differential mis-operations occur with these traditional methods as a result of CT saturation, DC offset, or current subsidence. One reason is because the traditional operating and restraining principles rely heavily on the current magnitude,...
Autoreclosure provides a means of improving power transmitting ability and system stability. The conventional reclosure adopts the fixed dead time interval strategy, that is, the reclosure is activated after a time delay to restore the system to normal as quickly as possible without regard to the system conditions; however, these simple techniques cannot give the optimal operating performance. For...
This paper deals with line protection challenges experienced in system having substantial wind generation penetration. Two types of WTGU: Doubly Fed (DFIG) and Squirrel Cage (SCIG) Induction Generators are simulated and connected to grid with single circuit transmission line. The paper summarizes analytical investigations carried out on the impedance seen by distance relays by varying fault resistances...
This paper presents a new multi-criteria stabilization algorithm of transformer differential protection. Proposed scheme bases on new criteria signals and appropriate operation thresholds. New algorithm employs fuzzy reasoning technique for better discrimination of inrush conditions. The developed stabilization algorithm has been tested with ATP-EMTP generated signals, proving to be reliable and much...
The new generation of current sensors, such as Rogowski coils, have performance characteristics that can improve design and operation of modern power systems. This paper presents novel solutions that integrate protection, control, and metering functions for power transformers and cables by sharing signals from the same Rogowski coils.
The paper presents a new pole slipping protection method that combines high efficiency of pole slip detection and sensitivity to many sources of potential pole slipping. To simplify the setup process the adaptive settings are calculated continuously. The new adaptive method utilizes active and reactive power measurements on machine terminals to ascertain that the synchronous machine is committed to...
When applied over asymmetrical or potentially asymmetrical channels (unequal channel propagation times in the transmitting and receiving directions), such as commercial-class SDH/SONET networks, line current differential schemes need an external time reference for current data alignment if the sensitivity of the differential scheme is to be preserved. Modern line differential schemes can handle a...
Accurate fault location on transmission lines becomes increasingly beneficial by reducing outage times and allowing faster restoration of scarce power system assets back into service. Having natural access to synchronized remote current data, line current differential protection schemes can incorporate multiterminal fault location algorithms, allowing for more accurate fault location compared with...
A common practice for improving electric service reliability is to provide an alternate source of supply. On the distribution system, two feeders — each with one or more mid-line overcurrent protective devices — can be tied together through a normally-open tie point to restore service to unfaulted sections of line. Conventional looped distribution systems rely on overcurrent coordination to ensure...
This paper presents an analysis of the main operating conditions that may lead to inappropriate differential protection operation. These conditions were simulated using the Alternative Transients Program (ATP) and the model of a real system. The saturable transformer was the main component of the ATP/EMTP simulations. The saturation and hysteresis effects are represented by a non-linear model of the...
This paper presents a novel protective concept for EHV Three-terminal transmission line, teed circuit. The proposed protective relaying techniques use the fourth sequential overlapping derivative, SOD, concept at all line terminals. The SOD signals represent the transient components initiated due to fault occurrence. Such signals are free of both dc and fundamental components. Two protective relaying...
This paper presents a novel approach designed for centralize substation level protection to determine the faulty feeder in a distribution network In opposite to phase-to-earth faults in the transmission networks (HV), which neutral points are solidly earthed, fault-loops in a fault-to-earth case in MV distribution networks have big impedance. Additionally during the earth-fault the transient component...
IEC 61850 supports the use of functional designs for specifying substation automation systems. However, specifying such systems is not standardized within IEC 61850. This means that utilities are somehow left in the dark regarding the use of the engineering process defined in IEC 61850–6 and therefore often revert to using traditional and proprietary ways to specify their requirements. To overcome...
High impedance fault (HIF) exposes great hazard for personal safety and property security. High impedance fault (HIF) in MV distribution with restricted fault current cannot be detected and cleared by conventional over current relays. In this paper, an integrated scheme utilizing different features of HIF is presented. Various documented field data has been investigated and summarized to get the most...
This paper presents a novel approach for the detection of abnormal power system states that force systems into blackout. K-means clustering techniques and two types of distances for identifying pattern clusters are used to detect abnormal conditions. PCA is used for the reduction of the data matrix for faster calculations. The proposed hybrid technique is then demonstrated on an IEEE 14-bus system.
On distribution systems similar to that shown in Figure 1, in the event of a single phase to earth fault, the source protection will trip on earth fault. After the source has cleared, an unearthed network is left, backfed via the primary substation. Other than a very low level charging current, no fault current will flow. UK Power Networks detect this by neutral voltage displacement (NVD). Where a...
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