Protection Of High Voltage Transmission Lines Research Articles

The Modeling and Simulation Research on High-Voltage Transmission Line Distance Protection Devices

Transmission line protection is a very important part of the power system. In order to effectively study the distance protection of high-voltage transmission lines, this paper introduces the setting and operation of distance protection., build the mode with Simulink tool box in the software of Matlab, and simulate the mode by S functions. The simulation results illustrate the Matlab software can effectively reflect the behavior of the distance protection when there are some faults in the simulated transmission line, which proves a simple and effective method to research the relay protection in the power system.

Instantaneous protection scheme for backup protection of high-voltage transmission lines

The protection scheme focused on in this study is a typical protection system used in high-voltage systems such as 132 kV, 275 kV, and 500 kV. The research will analyze the existing protection scheme for transmission lines that the power utility has implemented and will propose a new protection scheme to improve the performance of the existing scheme. The existing protection scheme currently implemented by the power utility for backup protection operation has a longer fault-clearing time and no restoration time, and it does not utilize support relays. This study will focus on a backup protection operation on high-voltage overhead transmission lines, which take up communication when the main protection has failed to communicate, the relay has failed due to loss of DC supply, or the relay function itself has been blocked. Moreover, all the support relays will be utilized in order to improve the protection system. The improvement will consider three elements, which are the fault-clearing time, fast restoration time, and relay utilization. Each improvement to the protection system will have its own philosophy and concrete rationale, which have advantages or disadvantages for the transmission line. The effect of the improvement scheme will also consider the outcomes in other schemes to ensure that time coordination does not overlap. Every possibility of a fault will be analyzed in order to have a clear understanding of the effects of the three elements. CAPE software will be used as a tool for simulation and to analyze its compatibility with real applications. CAPE software is able to model a real-life transmission line and is also able to simulate faults in the tested area. The results of the simulation show that the backup protection operation improved fault-clearing time and restoration time. It also increased the network's system stability, particularly during the occurrence of maximum fault currents.

Optimization of Hellenic overhead high-voltage transmission lines lightning protection

It is well known that the lightning protection of transmission lines is exclusively relying on their correct initial design. Although detailed engineering studies are usually performed by electric power utilities for the design of new transmission lines, there are reported cases where the design is based simply on tradition or on utilities’ standardization policy. In this paper, the lightning protection of high-voltage transmission lines is faced as an optimization problem where optimum design parameters are calculated for the lines, relating their cost with the lightning failures’ cost, aiming to reduce or even eliminate lightning failures. The optimization method considers all the available protection means, i.e. ground wires and surge arresters. In order to validate the effectiveness of the proposed method, it is applied on several operating Hellenic transmission lines of 150 kV carefully selected among others due to their high failure rates during lightning thunderstorms. The obtained optimum parameters, which reduce the failure rates caused by lightning are compared with the operating transmission lines’ existing parameters showing the usefulness of the method, which can prove to be a valuable tool for the studies of electric power system designers.

Artificial neural network-based software tool for calculating the lightning performance of high-voltage transmission lines

An artificial neural network (ANN) is addressed for evaluating the lightning performance of high-voltage transmission lines. Several structures, learning algorithms and transfer functions were tested to produce a model with the best generalising ability. Actual input and output data, collected from operational Hellenic high-voltage transmission lines, were used in the training, validation and testing process. The method is coded in a comprehensive software program to be used by electric power utilities as a useful tool for the design of electric power systems, as an alternative to the conventional analytical methods. The aims of the paper are to describe in detail the proposed ANN method and the developed software tool and to present the results obtained by its application to operational Hellenic transmission lines of 150 kV and 400 kV. The ANN tool's results are compared with results produced from a conventional method and real records of outage rate showing a quite satisfactory agreement. overvoltages in distributions lines (13) and for lightning protection of high-voltage transmission lines (14). The calculation of the lightning performance of overhead transmission lines presents many uncertainties owing to the random nature of the lightning phenomenon and the lack of reliable data. This is why all the existing methods for the calculation of lightning performance are based on empirical and approximating equations. ANNs can be an effective alternative solution to this problem, as they can present great accuracy and, in many cases, better results using only actual line data in the lightning performance calculations. Moreover, the efficient and economic implementation of ANNs with today's computer technology makes them very attractive tools. In this paper, an ANN method is proposed to identify the lightning performance of high-voltage transmission lines. By testing several combinations of different structures, learning algorithms and transfer functions, we have developed an ANN that presented the best generalising ability among all the other combinations. Actual input and output data, collected from operational Hellenic high- voltage transmission lines w ere used in the training, validation and testing process. The developed method was coded in a comprehensive software program and applied to several operational Hellenic transmission lines of 150 kV and 400 kV so that its accuracy could be validated. The results obtained are compared with those produced using conventional methods and with real records of outage rate.

Distance protection of high-voltage transmission lines

Distance protection of high-voltage transmission lines

Protector-Tube Application and Performance on 132-Kv Transmission Lines -- II

THE USE of protector tubes (previously referred to as expulsion protective tubes or “deion” gaps) during the past five years or so as devices for protecting transmission lines and equipment against lightning has gained considerable headway, particularly in the protection of high-voltage transmission lines. A number of applications have been made in the medium voltage transmission field, a few in the low-voltage field, and a number of scattered installations for protection of equipment and cables.

Protector-tube application and performance on 132-kv transmission lines — II

THE USE of protector tubes (previously referred to as expulsion protective tubes or “deion” gaps) during the past five years or so as devices for protecting transmission lines and equipment against lightning has gained considerable headway, particularly in the protection of high-voltage transmission lines. A number of applications have been made in the medium voltage transmission field, a few in the low-voltage field, and a number of scattered installations for protection of equipment and cables.