IEEE C37.66-2005 pdf free.IEEE Standard Requirements for Capacitor Switches for AC Systems (1 kV to 38 kV).
Abstract: Required definitions, ratings, and procedures for performing design tests, production tests, and construction requirements for capacitor switches for ac systems from 1 kV to 38 kV are covered.
Keywords: back-to-back capacitor switching, capacitor load, capacitor switches, inrush current, operation, pole discrepancy, probability of restrike classification, restrike, simultaneous operation.
IEEE C37.66 applies to single- or multi-pole ac switches for rated maximum voltage above 1 kV to 38 kV for use in switching shunt capacitor banks (see the note in this clause). This standard covers the application of capacitive load switching wherein the capacitive loads arc separated by sufficient inductance to limit the high-frequency transient-making peak current to the peak values shown in Table 2 and Table 3. Switches designed and built in accordance with this standard are not intended for use as fault current or non- capacitive load current interrupting devices.
NOTE—This standard is intended to be a comprehensive standard for all “specific duty” applications of switches in the area of switching shunt capacitor banks, but it is limited in scope up to and including 38 kV. However, subject to agreement between the user and manufacturer, it may be used as a specification guide for other rated voltages.
5. Ratings
5.1 General
When the interrupting medium is vacuum. the capacitor switch shall withstand the rated impulse voltage in the closed position.
However, the unique characteristics of an open vacuum interrupter or vacuum gap make it permissible to have random sparkovers of the open vacuum interrupter as much as 25% below the rated terminal-to- terminal lightning impulse withstand voltage of the capacitor switch. If such an impulse surge sparks over the open interrupter contacts, the impulse current will pass through the open contacts without damage to the interrupter unit. An impulse sparkover of the open vacuum contacts may be followed by a flow of power current that will be interrupted without damage to the capacitor switches.
Switches with interrupter mediums other than vacuum shall be rated as given in Column 5 of Table I for both the line-to-ground and open gap conditions.