DISTRIBUTION EQUIPMENT REVISED AS AT 24 june2012.ppt - DISTRIBUTION EQUIPMENT start Definition \u2022 These are electrical apparatus which help in running

DISTRIBUTION EQUIPMENT REVISED AS AT 24 june2012.ppt -...

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Unformatted text preview: DISTRIBUTION EQUIPMENT start Definition • These are electrical apparatus, which help in running out of distribution lines over long distances from substation. also help in; • -Identifying the electrical line fault. cont •Sectionalizing during maintenance •-Transfer of loads incase of breakdown / shutdown of a substation •-Improvement of line voltages (AVRs) cont • -Connecting a new HV line • -Introducing a new substation (GMT or pole mounted) among others lines constructed as overhead lines or underground cables – distribution; crossing of 66kv or 132kv – underground preferred CONTINUATION OCB – Oil Circuit Breakers. Uses oil to quench the arc between the contacts-located within the 132kv/66kv;66kv/11kv substations. start point of the 11kv feeder. – A.C.B – uses air for the same, e.g. sulphur dioxide. (sf6 gas)m • cont – OD Unit – Oil immersed unit (switch); has three modes i.e. – SERVICE,OFF,EarthPositions , respectively -VL Unit – Has oil immersed fuse – switch has an auto mechanisms Operates to open a switch when powder fuses blows hence latches the mechanism cont -VL Unit – Has oil immersed fuse – switch has an auto mechanisms Operates to open a switch when powder fuses blows hence latches the mechanism WHERE THEY ARE USED ) O.C.Bs- Incomer protections and feeder • i protections for 11kv and 33kv line to interrupt breaker in case of a fault. Isolate the healthy ones from the faulty circuit • ii) A.C.Bs – Used for bus bars, transmission lines sometimes on feeder protection and capacitor Banks protections. As (I) above more expensive to maintain • • Fuse mounts- withdraw able units installed on spur lines and transformer. The units carries fuse elements that protects the equipment against high current • Taplin Isolators – Installed on spur lines to produce flexibility during maintenance • OYT- Oil (11kv) tripper – used for long distribution line; has ability to sense faults ahead; trips three times and opens the section ahead • OYS – Oil (11kv) sectionalizer; operates under dead condition and installed ahead of OXT. If the fault is ahead of OYT, OYS opens the section ahead of it and OYT heads • FTU/ Others- Fault tolerance unit – assist cont • iii) OD Units- Used at customers side (connection) –end of 11kv cable. Sometimes with VL unit (RMU) With oil to quench the arch. • iv) R.M.U – Ring Main Circuit (unit) – similar to OD but has VL unit for transformer protection cont • LINE – EQUIPMENT: (DISTRIBUTION). SECTIONALIZERS: • Equipment installed along the line to assist in locating faults whenever they occur along the system. They are either manual or automatic • They include; Fuse mounts;Taplins isolators;OYT;OYS;FTU / Others;AVRs;OXT continuation –TX- This is a transformation equipment from; – 11kv / 0.25kv; – 11kv/.0433kv; – allows customers to be supplied with the required phase voltages. Can be; •single phase; three phase • Has; windings, oil and tap changers, also has • -11kv bushings • -lv bushings cont • For the customers to be connected there must be a transformer of either transformation i.e.; 33kv / 0.433kv; 33kv / 025kv;11kv / .433kv;11kv / 0.25kv • ratings are; 200kva , 315kva, 50kva, 100kva, 25kva, 15kva, 5kva, • Generally each domestic customer is rated at 3kva up to 8kva;commercial is beyond this value. continuation • – RMU- Ring Main Unit – Houses VL for protection – TX- This usually a step –down 11kv / 0.25kv, 11kv/.0433kv equipment which allows customers to be supplied with the required phase voltages. Can be; •single phase •three phase cont • Has; windings, oil and tap changers -11kv bushings • -lv bushings • -arcing horns • • For the customers to be connected there must be a transformer of either transformation i.e.; 33kv / 0.433kv; 33kv / 025kv;11kv / . 433kv;11kv / 0.25kv • ratings are; 200kva , 315kva, 50kva, 100kva, 25kva, 15kva, 5kva SURGE DIVERTERS •These are units that are installed on transformers and high voltage cables. Do divert any excessive current and direct it to the ground .The unit is connected on the lower side to the earthed structure. Importance of these equipment in operation of the system. • Assist in handling problems of customers on matters associated with power failures. • Clearing well any queries related to dim lights. Particularly domestic customers. • Better knowledge on maximization of customers (projects). • Frequent power blackouts due to blown fuses & taking necessary action. • cont • make the customer understand need for shutdowns. • Update the customers on new developments to perfect the supply. • Assist in faster solving of customers problems on the site to satisfaction. • Co-operation with the customers in order to eradicate vandalism. • Letting them understand the need for company to maintain the set standard and specifications. E.g 600m for the furthest connection. cont • Importance of reporting fast any fault at customers premises to avert danger. • Precautions the customer should take incase of a fault associated with any nearby distribution equipment. • Improves the customers-company’s employees relationship hence understanding customers complains . • Respond first to customer & act to restore power. • FEEDERS-These are power lines which emanates from primary and distribution substations. Those which emanates from primary substation are referred to as primary feeders while those from distribution substation are called distribution feeders. • Primary feeders are usually those lines which transmit power from one primary substation to another. • • Their ratings are 200kv,132kv,and 66kv. Distribution feeders are the ones which deliver power to the secondary transformers which serves the Their ratings are 33kv and 11kv. • customers. • Main feeders are those lines which transmit or distribute power directly from the source transformers. • Any other line which tap power from these main lines are referred to as spur lines. ...
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  • Spring '18
  • Professor Obura Oluoch
  • Electric power transmission, Electrical substation, RMU- Ring Main Unit, OYT- Oil

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