distribution networks


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Distribution networks (D.N.W) department is a service sector in Vishakapatnam steel plant. It plays a vital role as it supplies power to all the sections in the plant. The major sections of this department include
Main receiving station (M.R.S)
Load block step-down substation(L.B.S.S)
Relays

The brief introduction of these sections is mentioned below,
Main receiving station :
This is a place where power (220kv ac) from A.P.S.E.B and from thermal power plant are received and synchronized . From here the power is distributed to various load block step-down substations such as L.B.S.S-2,
L.B.S.S-3,L.B.S.S-4.
Load block step-down substation :
Receives power at 220kv and step-downs to 33/11/6.6 kv by transformers for distribution of power in blocks to shops.
Thermal power plant :
Power generated at 220kv is transmitted to M.R.S and is also distributed to load block step-down substations such as L.B.S.S-1 and L.B.S.S-5.
Underground cables :
These are used for transmission and distribution of power.

Voltage levels of power distribution at VSP :
Extra high voltage : 220kv
High voltage : 33/11/6.6kv
Medium voltage : 440v
Low voltage : 250

SOURCES OF POWER :

Power requirement of VSP is met through captive generation as well as supply from APSEB grid. The captive capacity of 270 MW is sufficient to meet all the plant needs in normal operation time. In case of partial outage of captive generation capacity due to breakdown, shutdown or other reasons, the short fall of power is availed from ABSEB grid. Turbo Generators of VSP normally operate in parallel with state grid. Excess generation over and above plant load is exported to APSEB.
The agreement with APSEB provides for a contract demand of 150 MVA and permit export of power. Tariff for import, export, demand charges, penalties etc. are stipulated. For purpose of billing, import and export energy is separately metered at Main Receiving Station.

Unit cost of power :

Generation cost : RS 1.31
Import energy : RS 3.42
Import demand per KVA :RS.195
Export energy :RS 1.76



POWER REQUIREMENT :

Integrated Steel Plants are major consumers of electricity, with specific consumption of power at around 600-650 kWh/Ton of liquid steel. The estimated annual power requirement of Visakhapatnam Steel Plant, at full level of production in each shop (corresponding to 3.0 MT of liquid steel), is 1932 million kWh. This corresponds to an average demand of 221 MW. The estimated energy consumption and average demand of major shops is given below: