18047364 Project on Substation 220kv 132kv

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Transcript of 18047364 Project on Substation 220kv 132kv

Hi this is a project on a 220 kV Grid substation in Sarusajai, Guwahati, Assam Most of the documents are taken from different search engines and I am not responsible for any wrong information here. All the data are from the substation itself. -Preetom Parasar

1. Introduction: 1.1. About the substation:1

The substation in Sarusajai, Guwahati-781034, Assam was completed by the year 1986 under AEGCL; it is one of the largest power grids in the state of Assam and the north eastern India. This substation has the capacity of 220kv and can step down to 132kv using three input lines through the incoming feeders. The input feeders are namely: AGIA- i; AGIA-ii; LONGPI- i; LONGPI- ii; SAMUGURI-i; SAMUGURI- ii. All these feeders come into the substation with 220kv. The substation has another substation under it. The capacity of this is 132kv/33kv. This substation was completed by the year 1997 under AEGCL. The purpose of this station was to step down the 132kv to direct distribution to the 33kv/11kv substations in six different areas of the state. The substation of 132kv/33kv has six outgoing feeders, namely: JWAHAR NAGAR, GARBHANGA, MIRZA, PALTAN BAZAR, and Kahilipara STATION. These out going feeders are of 33kv line. The most important of any substation is the grounding of the instruments, transformers etc. used in the substation. For grounding of the substation a metallic square or some poly shaped metal boxes are placed in the ground. These ground the extra high voltage to the ground. As it is dangerous to us to go near the instrument without proper earth. If the instruments are not ground properly they may give a huge shock to anyone who would stay near it and also it is dangerous for the costly instrument as they may get damaged by this high voltage.

1.2. Construction Site Selection & LayoutE HV S U B STATION EHV Sub-Station forms an important link between Transmission network and Distribution network. It has a vital influence of reliability of service. Apart from ensuring efficient transmission and Distribution of power, the sub-station configuration should be such that it enables easy maintenance of equipment and minimum interruptions in power supply. Flexibility for future expansion in terms of number of circuits and transformer MVA Capacity also needs to be considered while choosing the actual configuration of the sub-station. EHV Sub-Station is constructed as near as possible to the load center. The voltage level of power transmission is decided on the quantum of power to be transmitted to the load center. Generally, the relation between EHV Voltage level and the power to be transmitted is as follows: S.NO. POWER TO BE TRANSMITTED VOLTAGE LEVEL 1) Upto 150 MVA 132 KV. 2) From 150 MVA to 300 MVA 220 K.V. 3) 300 MVA to 1000 MVA 400 K.V. 1.3. SELECTION OF SITE 2

Main points to be considered while selecting the site for EHV Sub-Station are as follows: i) ii) iii) iv) The site chosen should be as near to the load center as possible. It should be easily approachable by road or rail for transportation of equipments. Land should be fairly leveled to minimize development cost. Source of water should be as near to the site as possible. This is because water is required for various construction activities; (especially civil works,), earthing and for drinking purposes etc. The sub-station site should be as near to the town / city but should be clear of public places, aerodromes, and Military / police installations. The land should be have sufficient ground area to accommodate substation equipments, buildings, staff quarters, space for storage of material, such as store yards and store sheds etc. with roads and space for future expansion. Set back distances from various roads such as National Highways, State Highways should be observed as per the regulations in force. While selecting the land for the substation preference to be given to the Govt. land over private land. The land should not have water logging problem. The site should permit easy and safe approach to outlets for EHV lines.

v) vi)



ix) x)


Process of Land Acquisition After the selection of site of the proposed EHV Substation and finalization of the area required, proceedings for acquisition of land have to be initiated. The acquisition of land generally takes quite a long time. Forecasting and planning of substation and selection of substation site needs to be done much in advance taking into account the normal period of acquisition of land. The acquision of land should not in any way disturb the commissioning of programme of sub-staion. In MSETCL a land acquisition is carried out by the concerned Civil wing. The proposal for acquisition of land is submitted to the District Collector in case of Govt. land and to the land 3

acquisition officer in case of private land through the PWD Authorities accompanied by following documents:(i) (ii)

7/12 abstracts along with the resolution of local authority. Village map with suitable land duly marked on it.

(iii) Sales statistics around the area.

(iv) (v) (vi) (vii)

No Objection Certificate from the Forest Deptt. if applicable. The certificate in case of private agricultural land that the owner of the land does not become landless if his land is acquired. These papers should be submitted after their due scrutiny. The land selected should be marked on the village map by taking joint measurements with Revenue Authorities. Once the proposal is submitted to land acquisition officer further legal proceedings are completed by him, and the award is given followed by allocation of land to the utility.

Possessions of land are taken by taking joint measurements. 1.5. STORAGE OF EQUIPMENTS FOR THE SUB STATION:

All the substation equipments / materials received on site should be stored properly, either in the outdoor yard or in the stores shade depending on the storage requirement of that particular equipment. The material received should be properly counted and checked for any damages / breakages etc. The storage procedure for main equipment is as follows:i)

EHV C.T.s and P.T.s Normally, 132 KV C.Ts. and P.Ts are packed and transported in wooden crates vertically while those of 220 KV and 400 KV are packed in iron structures for extra supports with cross beams to avoid lateral movement. 132 KV C.Ts. and P.Ts. should be stored vertically and those of 220 KV and 400 KV should be stored in horizontal position. C.Ts and P.Ts. packed in wooden crates should not be stored for longer period as the packing would may deteriorate. The wooden packages should be stored on a cement platform or on M.S. Channels to avoid faster deterioration of the wooden crates. C.Ts and P.Ts packed in iron cases stored in horizontal position should be placed on stable ground. No C.Ts and P.Ts. should be unpacked in horizontal position.


L.A. s. and B.P.I. These are packed in sturdy wooden case as the porcelain portion is very fragile. Care should be taken while unpacking, handling and storage due to this reason. iii) Batteries, Acid, Battery charger C & R panel, A.C.D.Bs copper piping, clamp connectors, hardwares etc. should be stored indoor. 4




Circuit breakers: The mechanism boxes of 33 KV V.C.Bs should be stored on raised ground and properly covered with tarpaulins or should be stored in door. The interrupter chambers should be stored on raised ground to avoid rain water in storage area. E.H.V. C.B. Now-a-days SF6 circuit breaker are used at EHV rottages. The control and operating cabinets are covered in polythene bags and are packed in wooden and iron crates. These should be stored on raised ground and should be covered with tarpaulins. The arcing chambers and support insulators are packed in iron crates and transported horizontally. The +ve pressure of SF6 gas is maintained in these arcing chambers to avoid the ingress of moisture. It should be ensured that this pressure is maintained during the storage. Other accessories like pr. Switches, density monitor, Air Piping, control cables, wiring materials, SF6 gas pipes; SF6 cylinder should be stored in store shed. Power transformers: The main Tank - The transformer is transported on trailor to substation site and as far as possible directly unloaded on the plinth. Transformer tanks up to 25 MVA capacity are generally oil filled, and those of higher capacity are transported with N2 gas filled in them +ve pressure of N2 is maintained in transformer tank to avoid the ingress of moisture. This pressure should be maintained during storage; if necessary by filling N2 Bushings - generally transported in wooden cases in horizontal position and should be stored in that position. There being more of Fragile material, care should be taken while handling them. Rediators These should be stored with ends duly blanked with gaskets and end plates to avoid ingross of moisture, dust, and any foreign materials inside. The care should be taken to protect the fins of radiators while unloading and storage to avoid further oil leakages. The radiators should be stored on raised ground keeping the fins intact. Oil Piping. The Oil piping should also be blanked at the ends with gasket and blanking plates to avoid ingross of moisture, dust, and foreign

All other accessories like temperature meters, oil flow indicators, PRVs, buchholtz relay; oil surge relays; gasket O rings etc. should be properly packed and stored indoor in store shed. Oil is received in sealed oil barrels . The oil barrels should be stored in horizontal position with the lids on either side in horizontal position to maintain oil pressure on them from inside and subsequently avoiding moisture and water ingress into oil. The transformers are received on site with loose accessories hence the materials should be checked as per bills