This is an article on technical subject pertaining to 33/11KV substations. In APCPDCL most of the substations are designed for two power transformers, two 33KV incoming sources (one regular and one alternate supply) and will be feeding six to eight 11KV feeders. Generally, substations will be fed from one source. In this condition all the feeders, station transformer, potential transformer, auxiliary equipment are fed from one source. But when the substation is fed from two different 33 KV sources at a time due to some technical reasons, then one power transformer will be fed from one source and other power transformer will be fed from other source. This is done by opening the bus coupler on 33KV bus and 11KV bus. On separation of 11KV bus, the station transformer will be on one side of the bus only. The station transformer will be feeding auxiliaries, substation lighting, fans etc and substation lighting and fans will indicate presence of incoming supply most of the cases. When the 33KV source feeding the station transformer via power transformer fails, the operator knows it by observing the condition (off status) of fans and lights in the control room and takes action required.
One of the most frequent problem faced in power line ( LT, 11 KV and 33 KV) erection is boring a hole of required standard depth. Many times we find that the poles are not buried to proper depth. As a result we are seeing bent poles and ultimately line breakdown causing much inconvenience to consumers and revenue loss to company along with unnecessary repair costs.
The following machines are the technological solution…..
1) Pit Boring Making Machine
I would like to share some of the tips which can help in ascertaining failure of a distribution/power transformer and also in repair of the same. SPM/TRE Engineers in particular must have these on finger tips.
All most all the three phase distribution/power transformers we have in the system are delta/star connected with capacity ranging from 16 KVA to 12500 KVA. We have to conduct many tests to establish failure of a transformer but we have to have alternate three phase/single phase supply which may not be available at the failure locations. At such instance a simple tong tester and insulation tester will be sufficient and serves the purpose in more than 90% of the cases
Present Procedure: At present APERC approved new ISI methodology for estimating agricultural energy is being adopted which is summarized as follows:-
- Energy meters are installed at LV Side of sampled (selected) Agl. DTRs of different capacities in each Mandal of the Circle
- Monthly readings are taken manually and through MRI by an outsourcing agency till recently. Now it is instructed that AEs (Opn) shall take readings from here onwards.
- Out of the sample DTR readings obtained only valid DTR readings which shall be at least above 50% as per APERC directions will be taken into consideration for estimation of Agl. Consumption. 10% of total sampled DTRs in all capacities are to be changed from month to month for better projection of sampled consumption.
- LT line losses are deducted as per APERC guidelines communicated in which LT lines are classified into 9 groups based on DTR capacities and no of LT circuits and losses are fixed for each groups as follows.
India has a vast scope in the field of energy conservation. Outdated technologies have made Indian systems highly energy “inefficient”, and this has eventually resulted in a gap between the electrical energy supply and the abnormal, “never-before” demand, which has been increasing despite huge outlay for energy sector since our independence.
Energy efficiency and conservation, in the past have been neglected on the blind assumptions that the Earth has a forever availability of the fossil fuels, whose worth is being realized lately. The energy efficiency should be done with full missionary zeal and dedication, any half hearted approach would definitely bound to fail, and to attain this without any failure, the consumers also owe responsibility to utilize the energy conservatively and most judiciously, by accepting a few hard shunned facts that the government alone shouldn’t be blamed and criticized and be expected to bear the entire burden of ensuring progress. Participation by the citizens is mandatory.