ELECTRICITY: How Nigeria recorded two total system collapse, still counting
By Eyo Nsima
There are strong indications that Nigeria’s power sector is still threatened by many problems, which culminated in the occurrence of two system collapse, according to the Nigerian Electricity Regulatory Commission, NERC.
In its just-released Second Quarter 2020 Report, the Commission, stated: “The industry witnessed a slight decline in the stability of the grid network during the second quarter of 2020 relative to the first quarter of 2020.”
System collapse
Specifically, it stated: “Similar to the preceding quarter, there was no incident of partial system collapse (i.e., failure of a section of the grid) during the second quarter of 2020. However, the industry recorded two (2) total system collapse (i.e. total blackout nation-wide) during the second quarter of 2020 as compared to one (1) total system collapse recorded during the first quarter of 2020.”
The report also, stated: “As highlighted in the preceding reports, to further improve the grid stability and prevent system collapse in subsequent quarters and beyond, the Commission in collaboration with the TCN shall intensify efforts to ensure further improvement in the grid performance.”
Monitoring
It stated: “The Commission shall intensify the monitoring of strict compliance to the SO’s directives to generators on free governor and frequency control mode in line with the provisions of the subsisting operating codes in the electricity industry. Furthermore, the Commission has reviewed the outcome of the competitive procurement of spinning reserves conducted by the TCN and its’ decision has since been communicated to TCN for further action. This is to guarantee adequate spinning reserves for proper management of the grid by the SO.”
Grid Frequency
However, on gride frequency, the report stated: “Based on the provisions of the Grid Code, the system frequency, under normal circumstances, is expected to be between a lower limit of 49.75Hz and an upper limit of 50.25Hz. The Grid Code, however, provides for grid frequency to operate between 48.75Hz – 49.75Hz (lower bound stress) and 50.25Hz – 51.25Hz (upper bound stress) when the grid is stressed.
“The system frequency pattern from January to June 2020 represented in Figure 6 shows a slight improvement instability. During the period under review, the system’s low frequency made significant progress towards the nominal regulatory standard as it averaged at 49.69Hz. However, the system high frequency, which hitherto was above the upper regulatory limit with a slight margin of the average of 0.47Hz in the first quarter 2020, was diverging further from the upper limit during the second quarter of 2020 with an average margin of 0.52Hz at the end of June 2020.”
Voltage Fluctuation
It also stated: “Similar to the frequency pattern, the Grid Code allows for voltage fluctuation between a lower boundary of 313.50kV and an upper boundary of 346.50kV. Throughout the period under review, both the High and Low system voltages were outside the prescribed regulatory boundaries. As stated in the preceding quarterly reports, frequency fluctuation and other harmonic distortion will result in poor power quality that could damage sensitive industrial machinery and equipment that are connected at high levels.”
It added: “To minimize the frequency and voltage fluctuations, the Commission shall continue to work with TCN and other relevant stakeholders to ensure that system voltage and frequencies operate within the prescribed regulatory limits in order to ensure safe and reliable electricity supply in NESI.”
