power distribution - Siemens

13SWITCHGEARMedium Voltage EquipmentGM-SG AccessoriesStandard Accessories Include:▪ Manual racking crank▪ Spring charging crank▪ Drawout extension rails (facilitate handling of circuit breakersin upper cell)▪ Lifting sling (for circuit breakers above floor level)▪ Split plug jumper (standard unless test cabinet is furnished)▪ Contact lubricant▪ Touch up paintOptional Accessories Include:▪ Circuit breaker lift device▪ Test cabinet (in place of split plug jumper)▪ Test plugs (if required by devices)▪ Electric racking motor assembly (to enable racking whileoperator is at a distance from the switchgear)▪ Manual or electrical ground and test deviceTest provisions, either a split plug jumper or a test cabinet, areavailable for testing the circuit breaker outside its cubicle.The split plug jumper is used to bridge the secondary disconnectswith a flexible cable, so the circuit breaker may be electricallyclosed and tripped with the control switch on the instrumentpanel while the circuit breaker is outside of its compartment. Thetest cabinet, including a control switch is used for closing andtripping the circuit breaker at a location remote from theswitchgear.Manual Ground and Test DeviceThis is a drawout element that can be inserted into a circuitbreaker cell. It opens the shutters, connects to the cell primarydisconnecting contacts, and so provides a means to make theprimary disconnect stabs available for testing. It is suitable forhigh potential testing of outgoing circuits of the switchgearmain bus, or for phase sequence checking. It also provides ameans to connect temporary grounds to de-energized circuitsfor maintenance purposes.The manual ground and test incorporates three-position singlepoleswitches (upper stabs to ground, neutral, and lower stabsto ground), eliminating the need for user-furnished groundcables. The switches are hook-stick operatable and are ratedfor the full momentary and short-time ratings of the associatedswitchgear. User-furnished grounding cables and commerciallyavailable ground clamps seldom have ratings equal to those ofthe switchgear.GeneralElectrical Ground and Test DeviceAn electrical ground and test device includes a power operatedswitch (derived from a GMSG circuit breaker) arranged to allowgrounding one set of disconnect stabs. Two devices, one eachfor the upper and lower stabs, are required if grounding isdesired to either side of the unit. The device also provides ameans of access to the primary circuits for high potential testsor for phase sequence checking. These devices are able toclose and latch against short circuit currents corresponding tothe ratings of the equipment. Due to the unique requirementsfrequently involved in such devices, all applications ofelectrically operated ground and test devices should be referredto Siemens for review.Note: Due to the special nature of ground and test devices,each user must develop definitive operating procedures forincorporating safe operating practices. Only qualified personnelshould be allowed to use ground and test devices.Figure 4: Accessory Cabinet13-10Siemens Power Distribution & Control, SPEEDFAX 2007-2008 Product Catalog