The gas-fired and hydropower Generation Companies (GenCos) have called on the Transmission Company of Nigeria (TCN) to improve the transmission networks to save their generating machines from recurring frequency oscillations.
Its umbrella body, Association of Power Generation Companies (APGC), told Daily Trust at the weekend that the “Frequency oscillations which are due to weak transmission network, have adverse effects on the generators, units and station auxiliaries in both the thermal and hydro power plants.”
APGC said one of the effects was the increase in both the machines’ fixed maintenance cost and variable maintenance costs.
The Executive Secretary of APGC, Dr. Joy Ogaji, said the about 24 operational GenCos are designed to operate optimally and efficiently at base loads but that operating less than these caused reduction in efficiency and a hike in gas consumption by 15 to 20 per cent which is not captured in the tariff – Multi Year Tariff Order (MYTO).
She said when system collapses occurred, the number of Start and Stops of those machines increased the machines and turbines’ Equivalent Operating Hours (EOH), triggering more maintenance costs.
APGC said the generating firms have been operating under high frequency which it described as ‘System Stress Zone’ in the grid code ranging from 48.75 Hertz (Hz) to 51.25Hz which is against the normal 49.75 – 50.25 Hz band.
“This high frequency is damaging the generators and it also induces high temperature and overheating in the rotor,” Ogaji lamented.
The GenCos therefore demanded the immediate installation of regulatory spinning reserve on the network as stated by the Grid Code formed by the Nigerian Electricity Regulatory Commission (NERC), and implementation of the reviewed payment for spinning reserve procurement. They also urged NERC to immediately intervene by ensuring strict adherence to the Grid Code by TCN.