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The paper will present implemented protection scheme on two, symmetrical, double core design Phase Shifting Transformers (PST) [6], each rated at 600MVA, 400kV, 866A, 50Hz, ±40° with in total 64 tap positions (32 advance and 32 retard). Thus, every individual tap introduce phase angle shift of 1,25°. The used PST protection scheme follows the protection recommendations published by IEEE [1]. It shall...
The present transmission systems are rapidly changing principally due to an increasing demand for better utilisation of existing lines resulting in lower transient stability limits, and also due to an increase in the complexity of the networks with small-scale distributed generation being connected into the existing networks. The current protection/fault location techniques are not conducive to such...
Distributed generation is increasingly likely to play a major role in electricity supply systems as recognition is made of its low carbon credentials. However, the integration of these units at distribution voltages is a major challenge for utilities. One particular issue is that generators may, unintentionally, continue to supply local demand when areas of the network are isolated from the main system...
The requirements for improvements in the efficiency and quality of protection schemes at the transmission and distribution level of the electric power systems highlights the need for development of new methods and tools that can help the industry achieve these goals. The paper describes an object-oriented engineering process for the development and implementation of protection schemes, the IEC 61850...
This paper reviews the characteristics of inrush current and analyses its causes. The development of digital substation and the concept of integrated protection are also outlined. The paper studies different models to simulate several kinds of inrush and internal short-circuit fault. Through these models, the new composite algorithm is analysed in order to verify the reliability and sensitivity of...
With the integration of large scale wind power, the characteristics of power system operation has been changing, and, some problems come forth. On-line security assessment and control decision support system provides the stability and security state message for dispatcher in time, and, some suggestions to improve the level of power system stability and security. To suit the requirements of large amount...
Integrating Distributed Generation (DG) in distribution systems will have an impact on the fault current magnitudes. This could have an impact on the coordination of the protective devices. In this paper, the optimal DG locations are determined in order to minimize the overall relay operating times for a meshed distribution system. The problem is formulated as a Non-Linear Programming (NLP) problem...
This paper provides a discussion on future direct current (DC) network development in terms of system protection under DC-side fault scenarios. The argument between appropriate DC circuit breaker and new DC fault-tolerant converters is discussed after a review on DC technology development and bottleneck issues that require proper solutions. The overcurrent/cost curve of power-electronic DC circuit...
Currently, there are many challenges in the development of numerical, multifunctional Intelligent Electronic Devices (IEDs) paraphrased as relays in this paper. These are to continuously improve the design quality, to reduce the development period for shorter time to market, and to optimise the development cost and the product cost. One effective solution for these challenges is to develop automated...
For decades, various versions of the Takagi algorithm have been used by microprocessor-based relays for fault location. This system provides accurate fault location, limited by nonhomogeneous infeed, load flow, fault resistance, and series-compensated or parallel lines. With the emphasis placed on reliability in today's power system, the need for improved accuracy in fault location has increased....
The digital substation and the implementation of IEC61850 are fundamental to the future of protection relays. The IEC61850 standard, "Communication Networks and Systems in Substation", provides the basis for the communication system for the digital sub-station's protection and control schemes. Section 9–2 defines the Ethernet based communication network providing data transfer between primary...
The new generation of current sensors has performance characteristics that can improve design and operation of modern power systems. This paper presents novel solutions for protection of capacitor banks using Rogowski coils as currents sensors.
In this paper the authors report current experience of IEC 61850 application in the Portuguese transmission system through the presentation of the Ermesinde case study. Adopted physical and logical architectures, function allocation, as well as engineering tools and processes are described and discussed. In the second part of the paper a future outlook for advanced transmission system automation is...
In this paper we describe recent developments in flexible protection schemes that make use of passive fibre Bragg grating (FBG) based transducers for the distributed measurement of voltage and current. The technology underpinning the passive optical approach is described in detail, and both the present development and the future potential of the approach are discussed. In co-operation with Toshiba,...
This paper provides an overview of recent developments in high availability networks and new redundancy protocols designed to guarantee seamless failover and proper functioning of the most critical substation automation applications such as tripping via GOOSE (Generic Object Oriented Substation Event) messages and IEC 61850 Process Bus based on switched Ethernet. The authors describe most common redundancy...
Transmission level protection functions are increasingly being looked at for Distribution systems. This can be attributed mainly to the enhancements being planned for by the Operating Companies, to increase the system efficiency, and also to ensure reliable power supply to the end Consumers. Slowly, the catch word "Smart Grid" is being consciously and progressively transformed to practical...
The advent of IEC61850 Standard has ushered a new age for substation automation. This standard has gained a very strong footing in Europe and its application is spreading across the world. In USA the progress towards IEC61850 implementation is relatively slower. IEC61850 holds great promises for substation automation and protection. There are many advantages that this standard brings to the area of...
Diagnosis of power system faults requires identification and classification of voltage disturbances in power systems and smart grids. The objective of this approach is to develop state of art signal classification algorithms for classifying different types of power quality disturbances (faults) based on latest improvements in signal processing and pattern recognition techniques. This paper proposes...
In this paper, a novel distance protection algorithm in frequency domain is introduced. Based on the R-L model of transmission lines, this algorithm is derived from the linear equations which are obtained in fault condition network and O-module network for single-phase-to-earth fault. Considering that transformers usually ground directly in high voltage power systems, a linear equation with three...
IEC 61850 is a standard that is now gaining pace within the Electrical Supply Industry and one that is under scrutiny by Network Rail. One of the key advantages offered by IEC 61850 is interoperability based on the fact a standard communications interface is implemented between substation devices. This allows the manufacturer to diversify specific functionality whilst allowing communication with other...
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