All-dielectric self-supporting(ADSS) cables are installed along with transmission line for the purpose of communication.During installation the outer layer of the cable is hydrophobic and is not prone to dry band arci...All-dielectric self-supporting(ADSS) cables are installed along with transmission line for the purpose of communication.During installation the outer layer of the cable is hydrophobic and is not prone to dry band arcing. These cables become less hydrophobic over time and become vulnerable to dry band arcing.This loss in hydrophobicity is because of the contamination formed on the outer layer due to pollution.This is one of the reasons which cause cable failure.Considerable amount of losses will be incurred on the occurrence of a cable failure as the cables are also leased to other companies.An improved equivalent circuit is used to calculate the voltage and current distribution of the double circuit line.A three-phase single circuit line and a three-phase double circuit line are used to calculate their corresponding voltage distribution and current distribution.The results could be used to predict dry band arcing on similar models.The method used considers sag,span and pollution on ADSS cable.展开更多
Considering the complex environment in 750 kV AC substation,porcelain insulators have particular electric field and voltage distribution in comparison with those used in AC transmission line,meanwhile,the investigatio...Considering the complex environment in 750 kV AC substation,porcelain insulators have particular electric field and voltage distribution in comparison with those used in AC transmission line,meanwhile,the investigation of a typical 750 kV AC substation located in Lanzhou with ultraviolet imager(UVI) demonstrated that the corona discharge of some insulators is serious due to the improper structure design and installation,so research on porcelain insulators used in substation is needed.The three-dimensional finite element method(FEM) 750 kV AC substation calculation model was established to calculate electric field and voltage distribution of insulators,and the voltage distribution curves along insulators which are classified by type and suspension location were obtained using a novel FEM method which can effectively reduce the calculation amount without losing accuracy,meanwhile,the effect of the grading ring for improving voltage distribution of insulators was studied by adjusting the structure parameters of grading ring. Consequently,an optimization structure of rings was proposed by improving the voltage distribution of insulator string and reducing the electric strength of grading ring for the purpose of restricting corona noise,and the onsite observations by UVI showed that the newly manufactured and installed grading ring could obviously avoid the occurrences of corona discharge which validates the optimization design.This paper proposed an effective method combining UVI observation and FEM calculation to study voltage-sharing characteristics of porcelain insulators,and the results can provide experiences and references for the design of 750 kV AC substation.展开更多
文摘All-dielectric self-supporting(ADSS) cables are installed along with transmission line for the purpose of communication.During installation the outer layer of the cable is hydrophobic and is not prone to dry band arcing. These cables become less hydrophobic over time and become vulnerable to dry band arcing.This loss in hydrophobicity is because of the contamination formed on the outer layer due to pollution.This is one of the reasons which cause cable failure.Considerable amount of losses will be incurred on the occurrence of a cable failure as the cables are also leased to other companies.An improved equivalent circuit is used to calculate the voltage and current distribution of the double circuit line.A three-phase single circuit line and a three-phase double circuit line are used to calculate their corresponding voltage distribution and current distribution.The results could be used to predict dry band arcing on similar models.The method used considers sag,span and pollution on ADSS cable.
文摘Considering the complex environment in 750 kV AC substation,porcelain insulators have particular electric field and voltage distribution in comparison with those used in AC transmission line,meanwhile,the investigation of a typical 750 kV AC substation located in Lanzhou with ultraviolet imager(UVI) demonstrated that the corona discharge of some insulators is serious due to the improper structure design and installation,so research on porcelain insulators used in substation is needed.The three-dimensional finite element method(FEM) 750 kV AC substation calculation model was established to calculate electric field and voltage distribution of insulators,and the voltage distribution curves along insulators which are classified by type and suspension location were obtained using a novel FEM method which can effectively reduce the calculation amount without losing accuracy,meanwhile,the effect of the grading ring for improving voltage distribution of insulators was studied by adjusting the structure parameters of grading ring. Consequently,an optimization structure of rings was proposed by improving the voltage distribution of insulator string and reducing the electric strength of grading ring for the purpose of restricting corona noise,and the onsite observations by UVI showed that the newly manufactured and installed grading ring could obviously avoid the occurrences of corona discharge which validates the optimization design.This paper proposed an effective method combining UVI observation and FEM calculation to study voltage-sharing characteristics of porcelain insulators,and the results can provide experiences and references for the design of 750 kV AC substation.
