Several areas in the city went without power for between six to ten hours after twin cable faults occurred almost simultaneously in the wee hours of Thursday.
One of the faults was isolated to the underlying cable joints at a transformer near Vel Sokkanathan Mandapam while the other occurred in the cable network near Nellithoppe.
Since around 4 a.m. when the first cable fault occurred in the transformer in the downtown Kamaraj Nagar and the problem erupted in Nellithoppe, several teams of field staff of the Puducherry Electricity Department were out on a major salvage operation through a large part of the day.
“We were able to isolate the fault at Nellithoppe within a few hours and restore supply to many areas by noon,” said K. Mathivanan, Superintending Engineer, PED.
However, power supply to areas fed by the transformer in downtown Kamaraj Nagar and surrounding areas remained disrupted till about 4.30 p.m.
Officials say that while cable faults are unexpected no matter how well maintenance works are carried out, the extended downtime before supply was restored is attributable to the ageing cable network that is carrying the ever increasing power load for low tension (domestic) and high tension (industrial/commercial) consumers.
“Some of the cables that support low tension consumer power demand are over four decades old. They were never intended to support modern-day peak power demand,” said a field engineer.
PED serves a consumer base of around 4.16 lakh which is predominantly domestic users (almost 75 per cent), followed by public lighting and commercial categories. The cumulative power demand for the UT is estimated to be in the 350 MW to 370 MW range and which is largely met by procurements from central generating stations such as the NTPC unit in Ramagundam, drawals from electricity boards of neighbouring States and the Neyveli Lignite Corporation. The power from its sole generating unit, the 32.5 MW combined cycle gas power plant in Karaikal, is consumed locally.
According to data for the last five years, there has been 11.5 per cent increase in the per unit power purchase cost. According to the PED’s Business Plan for 2016-17 through to 2018-19 submitted to the Joint Electricity Regulatory Commission, the department has been incurring losses over successive years due to under-recovery that has led to a widening expenditure-revenue gap.
In recent years, the spike in power purchase costs triggered by increase in fuel costs for generating stations is also causing a strain on the resources of the PED.
The problem for PED field staff is also that they are forced to adopt “trial and error” methods to identify underground cable snags as modern equipment and outdated cabling form a mismatch.
Resource constraints also hinder the PED from undertaking capacity upgrades on transformers in proportion to increasing load from the supply zone.
Besides, a few key Operations and Management posts as well as engineering manpower slots are laying vacant, sources said. These chronic issues persist even as the department is on its way to implement a Smart Grid modernisation scheme that aims to improve customer experience and cut transmission and distribution loss.
The stalled project of Power Grid Corporation of India, the nodal agency under the National Smart Grid Mission, seeks to modernise billing systems with technical and financial expertise of a Chinese firm.
The installation of smart meters is underway at households that would enable consumers to monitor real-time power consumption data and calibrate power usage.
From the PED perspective, these advanced meters would result in massive savings through monitoring of energy usage online, detecting malpractice or energy theft and even carrying out a connection/disconnection online. At present the transmission and distribution loss is 12.75 per cent with aggregate loss at 18.3 per cent and the goal is to bring T&D losses to about 10 per cent.
Spike in purchase costs triggered by increase in fuel prices puts strain on PED resources