CHAPTER 17
MINISTRY OF POWER

National Hydroelectric Power Corporation Limited

Chamera Hydroelectric Project, Stage -I (Project) of 540 MWs (three units of 180 MWs) was commissioned by National Hydroelectric Power Corporation Limited (NHPC) in April 1994. One of the units of the Project could not generate power on two occasions during 1996-97 and 1998-99 to 1999-2000 due to the failure of the Management in keeping critical spares and equipment in working condition. As a result, the Company incurred a loss of revenue amounting to Rs. 14.58 crore, besides loss of incentive of Rs. 24.77 crore. These two cases are discussed below:

On 5 February 1996, one of the units tripped due to gas leakage owing to failure of a gas tight bushing. Although spares required for replacement of the failed bushing were mandatory in nature and should have been kept in store as stand by, the Company did not ensure the availability of the mandatory spares in working condition. In fact, the consignment of original equipment along with spare bushing was received by the Company in soaked condition for which insurance claim was also lodged. However, the package containing spare bushing was not opened at the time of receipt. After arrival of the engineers of M/s. Siemens, Canada at site on 3 April 1996, the package was opened and spare bushing was not found fit for use.

Accordingly, NHPC had to place order for supply of the same on M/s. Siemens on 16 April 1996. On receipt of the bushing on 7 May 1996, the generating unit was synchronised with the grid on 12 May 1996. Even though sufficient quantity of water was available from 16 April 1996 to 12 May 1996, the unit could not generate power owing to non-availability of the critical spares. This resulted in loss of generation of 46.81 MUs, entailing loss of revenue amounting to Rs. 10.11 crore.

The Management stated (June 2001) that mandatory spares were kept in sealed condition as per the manufacturer's instructions and were opened only after arrival of the representatives of the manufacturer.

The reply is not tenable, as the initial spares arrived in wet condition for which insurance claim was also lodged by NHPC. Thus, the Company was aware that the initial spares were not in usable condition and as such should have ensured the availability of critical spares.

The project generates power at 13.8 KV, which is further stepped upto 400 KV level by a transformer for feeding the grid. The project had ten transformers each of 75 MVA capacity including one spare transformer. One transformer of a unit failed due to internal fault in its winding on 30 December 1997 and was replaced by a spare transformer. The unit was re-commissioned on 17 January 1998.

For repair of the defective transformer, matter was taken up with M/s. Pauwels, Canada. In July 1998, NHPC also issued purchase requisition to procure one additional transformer from M/s. Pauwels, ignoring the offer (24 January 1998) of Bharat Heavy Electricals Limited (BHEL). However, the Company could neither get the defective transformer repaired, nor procure the new one due to non-finalisation of the inspection charges demanded by M/s. Pauwels.

Meanwhile, another transformer developed internal fault on 30 March 1999. This time, the Company managed to get one defective transformer repaired from BHEL by cannibalising winding of another defective transformer and re-commissioned the unit on 16 June 1999. Subsequently, it also placed an order (21 June 1999) on BHEL for supply of additional transformer.

Consequently, one unit of the project could not be operated during the period from 30 March 1999 to 15 June 1999, due to non-availability of a transformer even though there was demand in the grid and sufficient water level in river. This resulted in loss of generation of 15 MUs causing avoidable revenue loss of Rs. 4.47 crore to the Company. Besides, it also lost incentive of Rs. 24.77 crore which it could have earned on account of availability of installed capacity above the normative level of 90 per cent.

The Management stated (June 2001) that it was a normal practice to purchase the transformer from the original equipment manufacture and repair of the defective transformer could not materialise due to dispute on the increase of Rs. 3.10 lakh in inspection charges demanded by M/s. Pauwels. They further, stated that BHEL was not in a position to repair the defective transformer for want of certain data relating to specifications, design, etc. of the transformer.

The reply is not tenable, as even after lapse of more than 15 months from the incident of first fault on 30 December 1997, the Company could not ensure the availability of one spare transformer despite the knowledge of high fluctuation of voltage in the grid. Further, BHEL was ready to supply the new transformer in January 1998 and ultimately, supplied the same in January 2000. If the Company approached BHEL for supplying the new transformer in January 1998 itself, it could have avoided the loss of revenue of Rs. 4.47 crore and loss of incentive of Rs. 24.77 crore.

The matter was referred to the Ministry in April 2001; their reply was awaited (October 2001).