Winnie Apiyo receives the 2017 Women in Energy Innovation Award

Topic: Automatic Blockage of Grid Energy Back Feed Project



REYKJAVIK, December 18 – In their second annual event, the 2017 Women in Energy Conference was held at Strathmore University in Kenya, with the theme of "Seizing the Opportunities". The conference focused on link between energy access and women empowerment. 

The event was held on the 13th and 14th of December with the support of the Ministry of Energy & Petroleum in Kenya, Brands and Beyond Ltd, KEPSA, and in collaboration with Strathmore University's Energy Center.

Attending the conference this year was ISE first-year graduate student, Winnie Apiyo, seen to the right. Indeed, Winnie did more than just attend the conference - she seized her opportunity and was the proud recipient of the 2017 Women in Energy Innovation Award.

Winnie received the 2017 Innovation Award for her work in the project titled "Automatic Blockage of Grid Energy Back Feed Project" which is detailed in her abstract below.

We at ISE could not be prouder. Congratulations Winnie on your accomplishments. 

Project Abstract

Elimination or optimization of Energy Back-Feed to the absolute minimum is one of the major transformation initiatives for the operations division. This was one of the outcomes of G2G project.The typical design of power stations is such that the Unit and Station Auxiliary Transformers are connected to the system side of the synchronizing circuit breakers. The separation point between KenGen and Kenya Power is the HV bushing of the Generator Step-up Transformers. Bulk energy meters capable of capturing both export and import energy are located at the separation points. With breaker open, energy drawn from grid is captured by the import register .With the breaker closed and the Unit generating, the total energy is partly delivered to the grid and the balance is channelled to the auxiliary plant via the Unit and Station power transformers. Energy delivered to the grid is captured by the export register of the bulk energy meter. KenGen bills Kenya Power for energy delivered to the grid using the export register. For stations operating with a capacity based power purchase agreement, the charge rate for energy component is extremely low. Kenya Power bills KenGen for energy drawn from the grid for auxiliary plant using the import register. The billing is at the normal exorbitant commercial rates. For stations with multiple Units, it is possible to minimize energy back-feeds from the grid. The station auxiliary plant and the associated switching schemes can be designed such that virtually all auxiliary plant power is drawn from the Units in generation modes so as to minimize the expensive energy back-feed imports to the absolute unavoidable minimum.

The metering voltage level at Kipevu I is 132kV. Currently, imports are metered at CI5 tariff .This back-feed energy from the grid is expensive since it is metered at the normal prevailing commercial charge rates. It should therefore be optimized to the absolute minimum for cost-effectiveness and energy efficiency purposes. The PPA energy charge rate for Kipevu I is Ksh0.28656 per KWh while the commercial charge per KWh of back-feed energy is Ksh6.6. Hence so long us the partial utilization of generated energy for auxiliary power consumption does not violate the plant contracted availability requirements, own power is preferred to the inordinately expensive back-feed power for auxiliary plant consumption.

As a long term measure, the automation of the switching at 415 V was carried out to ensure auxiliary power is drawn from synchronized Units whenever possible. This can be accomplished manually or automatically. Automatic changeovers are more effective. Manual changeover is not as effective since it is wholly reliant on human intervention. The implementation was phased with the Kipevu Energy Back-feed chosen to kick-off the project. The thrust was to automate the 415V changeovers so as to minimize the energy back-feed to the absolute unavoidable minimum and avoid unduly exposing staff to safety concerns associated with manual switching. 


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