WAPDA was established in 1958 and having a massive agenda, which includedgeneration, transmission and distribution of power along with irrigation, drainageand flood control etc. The electricity customers in the Pakistan is over 13 millioncustomers.There are four major power producers in country:1. WAPDA (Water & Power Development Authority),2. KESCO (Karachi Electric Supply Company),3. IPPs (Independent Power Producers)4. PAEC (Pakistan Atomic Energy Commission).
There 12436 km transmission line of 500KV,220 KVtransmission line in Pakistan.
The three-phase system has three sets of phase conductors. There 5077 km of 500 KV transmission line in Pakistan.LIST OF 500 KV GRID STATIONS1 Grid Station Sheikh Muhammadi Peshawar2 Grid Station Rewat3 Grid Station Sheikhupura4 Grid Station Gatti Faisalabad5 Grid Station Nokhar6 Grid Station New Multan7 Grid Station Muzafargarh8 Grid Station Sahiwal (Yousafwala)9 Grid Station Guddu10 Grid Station Dadu11 Grid Station Jamshoro12 Grid Station Nki
There are Thirty Two 220KV Grid Stations.Total length is 7359 km of220 KV transmission line inPakistan.
Transmission line poles or structures are between 60 and 140 feet tall. Different Transmission Structures
A typical high-voltage line has three phase conductors to carry the current and transportthe energy, and two grounded shield conductors to protect the line from direct lightningstrikes. Transmission lines use ACSR (aluminum cable, steel reinforced)An ACAR conductor is a stranded cable made of an aluminum alloywith low resistance and high mechanical strength. Bundle conductors are used to reduce corona losses andaudible noise. For 220 kV lines, two-conductor bundles are usually used
The safe and reliable transmission and distribution of electricity remains a major problemin Pakistan. losses from the transmission and distribution network totalled some 30% in2003/04.There are following main causes of loss……. Poor conductor material Weak grid infrastructure and substantial Theft of electricity Low time to time maintenance of network Resistive losses
After the transmission , Power is handed over to Eight Distribution Companies(DISCOs) to transfer this power to the consumers of Pakistan.1. PESCO: Peshawar Electric Supply Company, Peshawar, NWFP;2. IESCO: Islamabad Electric Supply Company, Islamabad;3. GEPCO: Gujranwala Electric Power Company, Gujranwala, Punjab;4. LESCO: Lahore Electric Supply Company, Lahore, Punjab;5. FESCO: Faisalabad Electric Supply Company, Faisalabad, Punjab;6. MEPCO: Multan Electric Power Company, Multan, Punjab;7. QESCO: Quetta Electric Supply Company, Quetta, Baluchistan;8. HESCO: Hyderabad Electric Supply Company, Hyderabad, Sindh.
At the substations,transformers reduce the voltage to a lower levelfor distribution to commercial and residentialusers. This distribution is accomplished with acombination of sub-transmission (33 kV to132 kV) and distribution (3.3 to 25 kV).Finally, at the point of use, the energy istransformed to low voltage .