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With the application of ultra-high-voltage (UHV) technology, how to reduce the construction cost of the UHV substations is becoming an important and emergent issue. In this paper, two kinds of one-column-varistor arresters are used to replace conventional four-column-varistor arresters for busbars or transformers or both of them. The switching overvoltage and lightning intruding overvoltage are calculated...
This paper provides catastrophic failure analysis of all three (3) station-class metal-oxide varistor (MOV) surge arresters located inside the metal-clad switchgear. All three surge arresters failed causing major damage to the switchgear without any evidence of switching surge activity. Analysis concludes that the B-phase surge arrester internal damage led to its thermal runaway. The exact cause of...
In this paper, switching overvoltages analysis based on the statistical study approach according to IEC 6007 Insulation Co-ordination are analyzed for the energization of the connected 115 kV underground and submarine cables from Khanom power plant to Samui Island substation. Comparative analysis of protection schemes including metal oxide surge arresters and controlled switching are analyzed for...
Every year there are several million lightning discharges occur over world. In power system perspective, lightning is one of the most serious causes of over-voltages. These over-voltages may cause flashovers and serious damage to the equipment and thereby imperil the supply of power to customers. Much of the power equipment in use today is susceptible to damage or service interruption due to striking...
Without protection, over voltages of lightning cause to damage electrical equipments. Many lightning discharges occur in distribution lines therefore protection of parallel passive filter (PPF) used to decrease harmonic currents is necessary. This paper analyzes the behavior of the parallel passive filter used to filter harmonic currents, during travelling waves and presents a method to protect the...
Switching over-voltage level plays a decisive role on the UHV equipments selection and equipment costs. This paper discussed the suppress effects of different methods. Two novel surge arresters under developing are introduced. Presently, the closing resistors are added to suppress the switching overvoltage, if low-residual arresters can be put into operation, the closing resistors need not be added.
We experimentally examined the possibility of the internal short circuit of an air switch due to the sparkover between different poles under the condition that no surge arrester exists in neighboring poles and one of three surge arresters is omitted at the pole with an air switch. Experiments at Shiobara Testing Yard and Akagi Testing Center of CRIEPI clarified the following. Fault current may flow...
In recent years, uprating of existing overhead power line has become a popular option for electric utilities to address increasing demand for power. Uprating overhead line by increasing voltage allows considerable increase in power transfer capability. This paper initially examines technical issues and conventional methods of uprating the voltage of overhead transmission lines. It then considers a...
This paper describes switching overvoltage of 345[kV] combined transmission system. Generally, switching overvoltage may cause the breakdown of insulation or joints of the underground power cable section. Therefore, in this paper, the various switching overvoltages are analysed according to the change of fault resistance, the amplitude of trapped charge and underground cable rate on 345[kV] combined...
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