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® WorleyParsons <br /> resources&energy <br /> in the neutral circuit to aid in identifying ground faults. <br /> Accessories will include a magnetic liquid-level gauge, pressure-relief device, sudden <br /> pressure relay, oil preservation device, valves for top and bottom filter press connections, <br /> drain/sampling valves, grounding pads, bushing-mounted current transformers, and hot <br /> spot winding temperature elements. <br /> The SUS transformers will include a manual de-energized tap changer located in the HV <br /> winding with taps ranging from 5 percent above normal to 5 percent below normal in 2.5 <br /> percent increments. <br /> 4.9 Power Distribution Centers (PDC) <br /> Power Distribution Centers (PDC) will house all 4.16kV switchgear and motor control <br /> centers, 480V voltage switchgear, low voltage MCCs, DCS panels, power and lighting <br /> panels, revenue metering, protective relaying, station batteries, CAISO RIG and other <br /> miscellaneous equipment. <br /> Each PDC will be equipped with redundant HVAC systems, smoke detection and lighting <br /> & convenience receptacles. Each electrical equipment area will be equipped with a wall <br /> mounted maintenance switch. This switch will be placed in the "maintenance" position <br /> whenever the switchgear area is occupied. When operated, this switch will remove all time <br /> delays in the main protective relays thereby making them essentially instantaneous trip <br /> relays. This action has the effect of lowering the arc flash hazard to a safe level as defined <br /> by NFPA 70E. <br /> The PDC will be shipped to site with all wiring completed between all internal <br /> components. <br /> 4.10 Medium Voltage Switchgear <br /> Two lineups of medium voltage switchgear will be provided. This switchgear will be 15kV <br /> class nominal, three-phase, three-wire with ratings not to exceed 3000A continuous and <br /> 50kA fault current duty. The medium voltage system will be high-resistance grounded via <br /> the CTG neutral grounding transformer when the generator breaker is closed, and will be <br /> ungrounded when the generator breaker is open. A set of zero-sequence PT's and ground <br /> fault protection are required for each MV switchgear bus to monitor for bus ground faults <br /> prior to closing the generator breaker. <br /> The medium voltage switchgear will be located indoors, will use vacuum interrupters, and <br /> will be rated to continuously distribute the full auxiliary load. Each lineup will contain <br /> voltage transformers, protective relaying for the GSUT, UAT, and feeder breakers and <br /> other load distribution equipment. All medium voltage breakers will be electrically <br /> operated from the DCS and equipped with a stored energy mechanism. <br /> Lodi Energy Center 3.4-5 LEC AFC <br /> 071608 Rev.A <br />