Politically speaking, the provision of adequate reserves is necessary to maintain a balance between the supply and demand sides in both complex and simple systems. In the life of an individual as well as in every family unit and social groups like financial systems, such entities are encouraged to set aside some reserves in the form of savings that will be useful during emergencies.

Similarly, a complex system like the national grid requires the provision of adequate reserves to be used during periods of stress and emergencies such as when there is loss of generation, extreme weather conditions, unexpected rise in load, transmission line outages, equipment failure etc. This requirement is statutory and is clearly spelt out in the grid code but is presently not being adequately complied with.

As contained in the grid code, the grid is supposed to be provided with Primary, Secondary and Tertiary Reserves to ensure the security of the system.

The grid code requires generators that are in service to provide Primary Reserves by setting their machines NOT to operate at their maximum rated capacity so that if there is any shortfall in generation due to either increase in demand or shortfall in generation, the machines will automatically respond to correct such imbalance.  This is presently being flouted because of GENCOs’ obsession with energy output, which is a vital component for the computation of their claims.

The Secondary Reserves are referred to as Spinning Reserves and should be purchased by the Market from the GENCOs to correct the operating frequency whenever there is an imbalance between the supply and demand sides. Apart from the market’s ability to pay for this service, a functional Supervisory Control and Data Acquisition (SCADA) scheme is required for proper monitoring of this reserve. Presently, the grid system has zero spinning reserves due to the absence of an effective SCADA system and Market illiquidity.

The Tertiary Reserves in the industry is called Under-Frequency Load Shedding (UFLS) Scheme and is expected to take out a predetermined load based on relay settings whenever the national grid system is stressed or an emergency occurs. Unfortunately, indiscipline is hampering the effectiveness of this scheme as loads are migrated away from feeders on which such relays are connected.

The near-absence of effective reserves on the national grid has compromised the security of the system hence the high occurrences of system collapses. It should be noted that the only means that is sufficiently (but not effectively) available for correcting imbalance in the grid system is the Manual Control Method, popularly referred to as “Load Shedding”. It lacks precision and is not very suitable for Real-Time operation.

In the light of the current unpleasant situation, the regulatory and operating authorities must insist on compliance with statutory requirements for the provision of adequate reserves for the security of the national grid system.