TCN achieves a major milestone in grid stability

01 Sep 2023
Sule Ahmed Abdulaziz


The Nigerian power grid maintains uninterrupted stability for over 345 consecutive days.

Transmission Company of Nigeria MD/CEO Sule Ahmed Abdulaziz

In a remarkable achievement, the Nigerian power grid has demonstrated an unprecedented period of stability, operating without any major disruptions for an impressive 345 consecutive days and counting. This milestone marks a significant advancement in the nation's efforts to enhance its power infrastructure and ensure reliable electricity supply to its citizens.

The sustained stability and reliability of the Nigerian power grid can be attributed to a combination of strategic measures and investments in the power system by the Management of Transmission Company of Nigeria (TCN). Several key components have contributed to this remarkable feat.

1.    Configuration and enforcement of free governor control

A three-man committee was formed by the Management of TCN, to go round the country for configuration and activation of Primary reserve, in conjunction with Power stations and in line with the provisions in the Grid code. The committee put a mechanism in place for the monitoring and enforcement of compliance of each generating station after the activation of the generating unit governor control. This makes most units in the grid to be on Free Governor Control compliance.

This mode of governor operation compensates for the change in frequency by change in generation automatically and is called Free Governor Mode of Operation (FGMO). A turbine governor is a component of the turbine control system that regulates rotational speed in response to change in load. As electricity demand is varying, the governor control maintain the output frequency to be within the statutory limit by adjusting the generator output.

This has helped a lot in grid stability, reliability, and has tremendously reduced transmission loss in the grid to allowable figures.

2.    Effective under frequency relay scheme

Under frequency works by monitoring the system frequency to see if it reaches a threshold below the operating frequency. If this occurs, the relay activates and can either automatically trip a circuit breaker or alert the network operator. This operates when the demand is more than output of generators at a threshold below the operating frequency.

Due to generation shortfall, the load demand is occasionally more than the generators output, thus result in decline of frequency below acceptable threshold. To address this decline frequency, which can result in cascade tripping of generators on under frequency and eventually lead to system collapse, the TCN Management implement a strategic deployment of under frequency relay scheme to operate in two critical stages of frequency to trip a specify load and restore the system frequency to acceptable value. The relays were carefully mapped and successfully deployed across TCN substations on rotational basis.

The implementation of free governor control and under frequency relay schemes enable the grid to be stable and reliable.

3.    Deployment of IoT/VPN for enhanced grid visibility  

Grid visibility has been the fulcrum for Grid operation and management. As efforts are being made to rehabilitate the SCADA/EMS system, the Management of TCN inaugurated a task force of in-house engineers that provided a stop-gap solution for the Grid visibility. As a result, the System Operators at the National Control Centre can see over ninety percent (90%) of the Generating stations and Transmission substations with the corresponding line flows. This well-considered choice has resulted in notable improvements in overseeing the power grid. By deploying IoT sensors, and devices development by the in-house TCN engineers, the ability for real-time monitoring has been established, enabling operators to proactively identify potential issues before they escalate into disruptive incidents. This predictive capability has played a pivotal role in maintaining the grid's stability. Moreover, continuous efforts are in progress to expand this visibility further by incorporating additional transmission stations through this IoT integration.

4.    Infrastructure upgrades / N-1 Contingency

The TCN Management has successfully ringed the Grid by meeting up with N-1 Contingency. By implication, the grid is no longer a radial network where tripping of individual line may cause instability in the system. The Grid is now a loop system due to massive investment in construction and dualization of critical circuits/lines.

The proactive efforts of the TCN management have led to substantial investments aimed at a comprehensive upgrade and modernisation of the transmission infrastructure. These strategic endeavours encompass a multifaceted approach, including the strategic commissioning of new transmission stations and the judicious installation of power transformers and compensating devices in areas where their impact is most needed.

This comprehensive modernisation drive has been instrumental in reinforcing the resilience and dependability of the grid. The newly commissioned transmission stations have not only expanded the network's reach but have also brought a heightened level of operational flexibility. The integration of power transformers has not only augmented the transmission capacity but has also led to improved efficiency, translating into smoother power flow and less susceptibility to bottlenecks. This reinforcement in the grid has improved the wheeling capacity of the Nigeria Transmission Network from 7.3GW in 2021 to 8.1GW in 2022.

Furthermore, the deployment of compensating devices in critical locations has effectively addressed power quality concerns, ensuring a consistent and stable supply. By minimising voltage fluctuations and reactive power imbalances, these devices have played a pivotal role in mitigating the risk of voltage sags, flickers, and other disturbances that could potentially disrupt the grid's performance.

Collectively, these strategic investments have significantly elevated the grid's operational capabilities, substantially lowering the likelihood of overloads or outages. The modernised infrastructure has not only met the growing power demands but has also positioned the power system to adapt to future challenges and evolving energy needs. The TCN Management's commitment to these upgrades underscores their dedication to providing a reliable and resilient power supply, contributing positively to both the community and the broader energy landscape.

5.    Enhanced maintenance regime

Maintaining the integrity of the power infrastructure has remained a paramount focus, encompassing a meticulous approach towards power plants, transmission lines, and substations alike. This steadfast commitment is exemplified through a series of concerted efforts, including regular inspections, prompt repairs, and the implementation of proactive, preventive maintenance strategies.

Regular and thorough inspections are conducted across the spectrum of power assets to identify any signs of wear, potential vulnerabilities, or impending issues. These assessments are instrumental in detecting even the slightest deviations from optimal functioning, ensuring that corrective actions can be swiftly taken before they evolve into more significant concerns.

In instances where faults or defects are identified, the emphasis on timely repairs is pivotal. Swift responses to rectify faults, replace worn components, or address any malfunction contribute to the overall health and efficiency of the infrastructure. This proactive approach not only prevents minor issues from escalating but also sustains the operational reliability of the entire power network.

Preventive maintenance measures further underscore this commitment to infrastructure sustainability. By employing a range of predictive and scheduled maintenance techniques, potential sources of failure are proactively addressed before they can manifest into critical problems.

6.    Proactive staff response

The team of trained, experienced, and dedicated staff members has consistently showcased their unwavering commitment through their proactive responses during times of emergencies. The rapid and well-coordinated actions, executed by well-experienced operators, have proven instrumental in averting potential crises from spiraling out of control. This collective effort has not only safeguarded the overall stability of the grid but has also effectively minimised disruptions that could otherwise have had far-reaching consequences.

Furthermore, their seamless collaboration and clear communication have played a pivotal role in maintaining a smooth workflow even under high-pressure circumstances. This has ensured a rapid response and fostered a sense of trust and confidence within the team.

Their dedication extends beyond their technical skills, as they consistently update their knowledge and refine their emergency response strategies through continuous training and learning. This commitment to professional growth underscores their determination to be at the forefront of grid management and resilience.

7.    TCN/NESI collaborative efforts

TCN Management, in close partnership with other stakeholders within the Nigerian Electricity Supply Industry (NESI), has cultivated a spirit of collaboration to effectively tackle challenges and execute cohesive strategies. Notably, initiatives such as Power Purchase Agreements (PPA), Service Level Agreements (SLA), Power Evacuation Agreements (PEA), and NESI situation room daily reports have been orchestrated through this joint effort.

The NESI daily situation room evaluations signify an active commitment to real-time monitoring and adjustment. By scrutinising grid performance on a regular basis, issues are promptly identified and addressed, bolstering the overall reliability and effectiveness of the power ecosystem.

This collaborative approach is effectively addressing the existing challenges while also ushering in a more resilient and robust power landscape.


The remarkable achievement of the Nigerian power grid in maintaining uninterrupted stability for over 345 consecutive days is a testament to the nation's commitment to enhancing its power infrastructure and ensuring reliable electricity supply. This accomplishment stands as a beacon of progress, driven by a combination of advanced technologies, dedicated personnel, strategic measures, and collaborative partnerships.

As Nigeria continues to stride towards a more sustainable and resilient energy future, this achievement serves as a powerful reminder of the potential for positive transformation within the energy sector. With unwavering determination, continued investments, and collective efforts, the nation is poised to further strengthen its power ecosystem, benefitting both present and future generations.

Sule Ahmed Abdulaziz is the Managing Director/CEO of Transmission Company of Nigeria.