One of the most important features of a stable, reliable and efficient power system is the availability of functional protection systems. The absence of protection systems or the lack of properly coordinated protection settings in the Nigerian Electricity Supply Industry (NESI) has led to several problems including deaths of innocent citizens, sudden and unwarranted loss of power supply, instability of the national grid, system collapses to mention a few. What is surprising though is that rather than deal with this important matter, operators prefer to trade blames.
The blame game in the NESI is laughable as whoever gets to the press first sways the view of the court of public opinion. More often than not, the transmission company of Nigeria (TCN) is first to go to press aledging that the distribution companies (DisCos) reject load, require capitalization, need to invest in their network etc to immediately shift the blame on the DisCos. Unfortunately, the Association of Nigerian Electricity Distributors (ANED), the umbrella body of the DisCos, is not in the habit of responding via a rejoinder except on rare occasions bothering on non-technical matters. Thus, TCN consistently engages in blame game and denigrate the DisCos by diverting attention from the main issues. The public deserves to know the truth.
The recent studies carried out by industry giant, Siemens, shows that the weakest link in the NESI is TCN. This assertion was borne out of a proper power system study. It revealed that the capacity of the distribution network is higher than twice the peak load ever transmitted by TCN. This has an important implication for the management of the NESI especially in terms of where investments should be directed. TCN must not be allowed to derail the Nigerian Electrification Roadmap (NER) Project by Siemens because they will want to hide their ineptitude and promote their desire to continue on a spending spree that leads to little or no improvement in the power system. This can make the NER project unsuccessful because the electricity network is interconnected. Improvements done on the distribution network but not coordinated with the transmission network will have little or no impact.
The sudden loss of load that results from a tripped DisCo circuit causes among other things, a voltage imbalance on the transmission network which in some cases, can destroy very expensive equipment in service. This can be made worse by the ferranti effect on a very long transmission corridor or a wrong mode of operation of shunt capacitors. Adequate system studies are required to determine the extent of possible damage and mitigations required perhaps through voltage balancing schemes, reactive power compensation, voltage surge protection etc.
Having said that, lightning strikes cause extreme overvoltages on power systems and for this, lightning protection is apt.
Power supply interruptions occurs more in the NESI due to problems caused by TCN than is reported. When it rains or even well before it does, feeders trip out. Possible causes will include the absence of tree and vegetation management on the network, lack of protection relays or the installation of improper settings on the relay. Short circuits develop and relays misoperate.
Sadly, TCN resists the coordination of the setting of their protection relays with the DisCos and the Nigerian Electricity Regulatory Commission now needs to insist that operators in the NESI (including the generation companies – GenCos) should submit the protection settings at interface points; all TCN-DisCos and TCN- GenCos interfaces, to enable a staged review of the coordination of protection systems in the NESI.
A lot of things have been done wrong in the NESI based on historical problems and most people prefer not to open the can of worms under their watch. So, carrying on with the errors and the old mentality of the NEPA days is the norm in the NESI. Any suggestion of a technical audit is been frowned at even when the purpose is to improve the system. However, it must not be that way. The purpose of a protection audit is to identify where the gaps are and to fix them over time. I am very confident that we sometimes lose power supply in the NESI for no reason other than for technical and operational inefficiencies.
Money is not a replacement for strategic thinking. The idea of throwing money at everything, obtaining loans and going on a spending spree without proper planning and detailed power system studies is a sheer waste of money. We have thus seen cases where large power transformers are installed in areas of little or no demand. This is embarrassing enough.
Regrettably, several transmission power transformers catch fire or go out of service for several hours, days or weeks without any investigation or report as to the cause of the outages. We have seen where newly installed transformers catch fire within months of installation – transformers that should last for over fourty years. TCN will only come out to say : “our engineers are working on a replacement”. No one is asking questions!!!
This is ridiculous and unacceptable in a power system. Every outage should be investigated and root cause analysis done to prevent reoccurrence. This glossing over the problem is milking the country dry and causing untold hardship on consumers. They just replace the faulty transformer and the new one catches fire again. The vicious cycle continues because no one in the management team has been penalised for it.
It is very clear that the entire power network is suffering from lack of maintenance and inadequate protection as the relays do not trip as at when required. A dangerous consequence of this can be the electrocution of innocent citizens as have been experienced variously in the NESI.
The problem at TCN-DisCos interfaces have to be professionally resolved for us to minimise blame games which only add to the woes of end-consumers who remain in darkness during the period when operators trade blames.
The coordination of protection systems in the NESI has to be done. TCN should not be allowed to resist it. Neither should the DisCos nor the GenCos. The purpose is not to shame anyone but to cause power flow in the Nigerian power system.
I am very sure that we regularly lose power supply based on inadequate protection settings as highlighted severally in many articles I have written on this blog.
Completing protection coordination and revision of protection settings philosophy for the NESI will lead to an improved power system.
The ministry of power should, as a matter of urgency, make a policy directive on this and the Nigerian Electricity Regulatory Commission will implement.
Idowu Oyebanjo is a power system protection engineer and writes from the UK.
