SEPS Technical Services WO-A-0082

The primary focus of these meetings was on Kajaki Units 1, 2, and 3, as well as the SEPS transmission and distribution systems. Discussions centered on the major system faults experienced by the generators, which are seeing faults on the order of 28 per day, resulting in premature wear and tear on Units 1 and 3. The Kajaki hydropower generators are experiencing major system faults, with the 13.8kV line serving the 10MV Tangi substation and the 110kV line serving the rest of the system being equally affected. The stator rewind of Units 1 and 3 is overdue, and either stator could catastrophically fail at any time, causing Unit 1 or 3 to shut down completely for at least 6 months. B&V stated that they have contacted all qualified subcontractors to rebuild a hydro generator such as Unit 2, but none are willing to work at Kajaki. The estimated time frame for installing Unit 2, assuming a subcontractor can be convinced to come to Kajaki, would require 3 years to complete, and an additional year to repair Units 1 and 3. This would mean a 4-year minimum time frame to increase the generating capacity by 19MW. However, it is unclear whether any of this additional generating capacity would reach the Kandahar area. The first priority should be to stop the daily frequent faults occurring on the transmission and distribution system, causing premature wear and tear of the generators. The current plan to replace many of the substations and divide out the distribution load may improve the situation, but it should be proven that DABS can get control of the distribution system before it is assumed that this will occur. An example is the Tangi substation, which continues to be overloaded beyond its 10MVA capability. The concern is that additional load being added to the system would exacerbate the overload situation, causing more faults and damage. The response from DABS crews was that they would be installing meters and removing illegal connections, but this belief should be proven before it is accepted as fact and acted upon. The desire to eschew the breaker and ½ substation designs proposed by B&V into simple radial systems will inevitably lead to increased downtime because the breakers in a radial design cannot be maintained without turning off some or all of the substation load. It is recommended that a ring configuration be considered for the Kajaki substation. The first priority should be to prove that the faults causing the generators to shut down can be eliminated or greatly reduced. Other means of providing additional electrical capacity, such as a new 110kV line from Herat or some method of generation at Kandahar, should also be evaluated.