Eaton VacClad-W Instructions For Installation, Operation, Maintenance

Also see for VacClad-W: Instruction booklet

Contents

15Instruction Booklet IB02201004EEffective October 2017Revision #4Instructions for installation, operation, andmaintenance of 38 kV type VacClad-W,150 BIL switchgear indoor housingsEATON www.eaton.comSection 6: Inspection and maintenance6.1 Safety precautionsRefer to the Safety precautions section of this manual WARNINGWHEN INSPECTING, REPAIRING, AND PERFORMING MAINTENANCE ONSWITCHGEAR, THE FACT THAT DANGEROUS VOLTAGES MAY EXIST MUSTBE KEPT IN MIND. PRECAUTIONS MUST BE TAKEN TO ENSURE THATPERSONNEL DO NOT COME IN CONTACT WITH ENERGIZED HIGH VOLTAGEPARTS. FAILURE TO DO SO COULD RESULT IN DEATH, PERSONAL INJURY,OR PROPERTY DAMAGE.Some common general precautions for high voltage work are:ConnectionsAll connections should be considered energized until the crewexpecting to work on them is ensured that the circuits are de-energized, and until every possible precaution has been taken to seethat there is no chance of a circuit being energized while the crew isworkingSwitchesSwitches, which have been opened to de-energize a circuit to permitwork on equipment, should be locked or blocked open, and a suit-able visible warning device placed on themGroundingDo not work on parts normally carrying current at high voltage untilthese parts have been disconnected and grounded to the groundbus The purchaser should make provision for connecting adequateflexible ground leads to every part of the switching equipment6.2 Access to switchgear parts6.2.1 High voltage partsVacClad-W switchgear is a metal-clad design All major parts of theprimary circuit are isolated by grounded metal barriers and enclosedwithin separate compartments For example, the circuit breaker,main bus, and primary line and load terminations are isolated fromeach other and enclosed in separate compartments, which are madefrom grounded metal barriers and covers Access to high voltageparts can be gained by removing the covers and barriers The coversand barriers should not be removed unless the parts to be exposedare de-energized6.2.2 Main contactsStationary primary disconnecting contacts (spouts) are locatedbehind the automatic safety shutters in the breaker compartmentUpper and/or lower spouts can be exposed by manually opening theshutters (see Figures 10 and 11) Do not expose any contacts unlessall upper and lower high voltage parts are de-energized WARNINGFAILURE TO DO SO COULD RESULT IN DEATH, PERSONAL INJURY, ORPROPERTY DAMAGE.6.2.3 Current transformersWindow type current transformers are installed over the stationaryprimary disconnecting contacts (spouts) in the front of the unit (seeFigure 11) All primary circuits must be de-energized prior to gainingaccess to any current transformers WARNINGFAILURE TO DO SO COULD RESULT IN DEATH, PERSONAL INJURY, ORPROPERTY DAMAGE.6.2.4 Tranformers and primary fusesA Removing transformers from the auxiliary compartment andreplacing fuses:1 Follow the instructions in the Installation procedure sectionof this manual, to remove the transformer drawer from theauxiliary compartment With the transformer(s) removedfrom the unit, unscrew the contact spring retaining screws(2) located at the end of the fuse tube Remove the fusefrom the tube and replace with a new fuse Reinstall thecontact spring on the new fuse and install the contact retain-ing screws (see Figure 8)6.2.5 Control equipmentWith the exception of apparatus such as current transformers andrear-mounted heaters, control equipment and wiring is generallyaccessible without exposing high voltage parts6.3 Inspection and maintenance scheduleTo ensure high-quality service, a definite maintenance schedule,systematically followed, is essential Plant, operating, and local con-ditions vary to such an extent that the schedule must be preparedto suit the conditions However, the following general requirementsshould be helpful in setting up the program WARNINGBEFORE ATTEMPTING ANY INSPECTION OR MAINTENANCE, BE SURETHAT ALL PRIMARY AND CONTROL CIRCUITS HAVE BEEN DE-ENERGIZEDAND GROUNDED AS REQUIRED, AND THAT PROPER STEPS HAVE BEENTAKEN TO BE SURE THAT THEY WILL REMAIN DE-ENERGIZED UNTIL ALLWORK IS COMPLETED. FAILURE TO DO SO COULD RESULT IN BODILYINJURY OR ELECTROCUTION. WHEN ENERGIZED, CIRCUIT CARRIESLETHAL HIGH VOLTAGE.6.3.1 Individual devicesThe maintenance schedule for individual devices such as circuitbreakers, relays, and so on, should be based upon recommendationscontained in the individual instruction book for the device Theseoperations should be coordinated with the overall program to resultin the least operating inconvenience and circuit shutdown6.3.2 Overall maintenanceThe switchgear installation should be given a thorough overallmaintenance check at the end of the first year in service becauseit provides an opportunity to evaluate conditions at an early point inthe life of the equipment Where conditions are abnormal, more fre-quent inspection and maintenance is necessary Where conditionswarrant, a longer period of time between maintenance periods maybe used The following require attention1 Buses and connectionsDe-energize the primary circuits and remove the cover platesfrom the primary compartments Before cleaning, takemegohmmeter (megger) readings between phases and eachphase to ground Inspect for signs of overheating or weakenedinsulation Remove dust from buses, connections, supports, andenclosure surfaces A vacuum cleaner with a long nozzle will beof assistance Wipe clean with distilled water and wipe dryAfter buses have been dusted and wiped clean, take meggerreadings again between phases and each phase to ground Keepa record of these readings for future reference in determiningwhen trends occur that would indicate a lowering of the insula-tion resistancePeriodic high-potential tests are not required after initial start-upand are recommended only after repair of high voltage buses orinstallation, or when the trend of megger readings indicates it tobe advisable Refer to Table 1