On technical requirements for Arc Suppression Reactors in the distribution circuit of 6–35 kV

Abstract

Development of the technical requirements for arc suppression reactors (ASRs) used for the capacitive current compensation of the single-phase earth fault is a critical task. The corresponding GOST (State Standard) 19470–74 “Oil-Filled Arc Suppression Reactors. Technical Requirements” is no more valid; automatically controlled reactors (with adjustable spacing controlled by magnetic biasing) are the mainstream; and completely new reactor designs, with the capacitor adjustment in particular, have become available. The standard guide for the earth-fault current compensation [1], not taking into account new technologies, has become obsolete. This paper considers the current criteria for the ASR application in the 6- to 35-kV networks and proposes new ones. It is proposed to use the residual earth-fault current, but not the ASR detuning coefficient, as the major criterion for capacitive current compensation of the single-phase earth fault; in this case, new requirements for the ASR and the network conditions characterized by active phase-to-ground and harmonics content currents are specified taking into account the electrical safety regulations. The problem of capacitance asymmetry is considered absolutely and relatively, and it is shown that the use of ASRs controlled by magnetic biasing allows omitting the network balancing and limitation of the asymmetry voltage at the level of 0.75% of the phase voltage. It is proposed to take into account these recommendations during development of an earth-fault current compensation guide and general technical requirements for ASRs and automatic tuning systems.