Politically speaking, greater attention is paid to the quantity of power delivered daily on the national grid because it is the yardstick with which the performance of the system is measured. This is not out of place as the public is generally interested in the Megawatt and Energy delivered to the Discos and the Regulator uses this quantity for settlement of claims.

Despite this situation, Operators of the system pay attention to the quality of voltage in the power supply delivered because most industrial and commercial machines are set to function at certain preset values and due to poor voltage, most organizations do not use public power supply in their operations. They prefer to put the public power supply as an alternative source.

Generators are expected to regulate the output voltage at their end with the help of their exciters and additionally, power quality equipment like Reactors, Capacitor Banks etc are installed at different Transmission stations on the grid to correct the voltage since voltage vary from one place to the other depending on several factors. Also, power Transformers are equipped with Tap-Changers that are used to achieve quality power supply. Other methods adopted to correct voltage imbalance include load management and the use of lightly loaded transmission lines.

Poor voltage quality can result into equipment damage, malfunction, inefficiency, and increased costs. This has reflected in damage to terminal equipment like Capacitive Voltage Transformers (CVT).

While in the Nigerian grid, the statutory limits prescribed at the 330kV level is set at 280.5 (lower limit) -346.5 (upper limit), the highest voltage recorded for some selected days on the national grid are as follows:

HIGHEST VOLTAGE RECORDED FOR SELECTED DAYS ON THE NIGERIAN NATIONAL GRID

S/N

DAY

DATE

HIGHEST VOLTAGE (kV)

LOCATION (TS)

1

MONDAY

05/02/2024

347

ONITSHA & FAKUN

2

TUESDAY

06/02/2024

348

ONITSHA

3

WEDNESDAY

07/02/2024

352

FAKUN

4

THURSDAY

08/02/2024

352

FAKUN

5

FRIDAY

09/02/2024

350

FAKUN

 

From the above table, it is clear that the highest voltage level consistently violated the prescribed statutory upper limit (346.5kV) and this has its implications on the system equipment and quality of power delivered to customers.

In order to mitigate the adverse effect of voltage values that contradict the statutory limits, concerned parties should focus on this variable by ensuring that GENCOs provide the expected services required in this respect and voltage correcting equipment are sufficiently installed at relevant locations across the grid for the benefit of both the industry and customers.