KAJAKI, Afghanistan -- Technicians with the U.S. Army Corps of Engineers’ Afghanistan Engineer District-South and Afghan engineers completed installation of switching equipment, July 11, at Kajaki Dam.
The installed equipment, known as a primary switch center, marks the first major improvement in a series planned by Afghan and U.S. government agencies to increase reliability and capacity on the Southeastern Electrical Power System in Helmand and Kandahar provinces.
The power plant services a number of key areas of southern Afghanistan including Sangin, Lashkar Gah, Kandahar city and Tangi. At Tangi, the line voltage is increased to 20kV to provide service to Musa Qal’ah.
The switch center is made up of a combination of large, high voltage air switch disconnects, circuit breakers and other protective circuitry. The switch equipment functions in a way similar to residential circuit breaker boxes — but on a much larger scale.
“Before the installation of the switch center, people in Helmand and Kandahar experienced a number of electrical outages every day, generally lasting for fairly long periods of time,” explained Chief Warrant Officer Thomas Black, deputy commander of Task Force Breshna Barq, a special task force under AED-South charged with providing engineering and construction services to support projects for SEPS.
“The switch center will reduce the length of time that the power is off with each outage, and it will protect the turbines from the wear and tear caused by the hard shutdowns,” added Black, a Phoenix native. “The switch center was specifically requested by DABS (Da Afghanistan Breshna Sherkat, the Afghan power utility company) to protect the turbines.
Engineers arrived on July 3, and with the help of local Afghan engineers, worked to upgrade the plant with the new 13.8kV switch center.
The new center will help reduce the total number of outages caused by shorts and overloads, said Black.
Prior to the installation of the new switch gear, if there was an electrical short circuit there was no buffer to interrupt the circuit and prevent the short from travelling straight to the dam’s turbines, which caused the plant to completely shut down. These shutdowns could potentially cause severe damage to the turbines in the shutdown process, Black added.
Plant shutdowns also negatively impacted the southerly 110kV transmission line which provides power to Sangin, Lashkar Gah and Kandahar.
“For most shorts and overloads, the new switch center will cause power to be cut off before causing damage to the turbines,” said Black. “Severe faults in the electrical lines may still cause the turbines to shut down, but there will be fewer of these instances, and the switch center provides an increased level of protection for the turbines when this happens.”
When such faults do occur, the 110kV line running to the south will remain unaffected by them.
The Kajaki Dam stands 75 miles northwest of Kandahar on the Helmand River. Originally built by the U.S. in 1953, the dam continues to fulfill its original purpose of providing downstream irrigation in the Helmand River Valley.
During the mid-1970’s, an American-funded hydroelectric power plant with two 16.5-megawatt generating units was installed at the foot of the dam. Two turbine generators were installed with space for a third.
“The plant was originally designed to put out 50 megawatts with each turbine producing 16.5 megawatts of power,” said Sgt. Terry Dietrick, a native of Lansing, Mich., and an electrician technician with AED-South.
Coalition forces transported a third turbine to the dam in 2008, but because of setbacks and unstable security in the region, were unable to complete installation.
According to Black, the equipment for the third turbine is now being inventoried and evaluated for installation under a contract managed by USAID.
“If we waited for the installation of the last turbine before installing the switch center, a problem could possibly damage a turbine permanently,” Black explained. “These turbines are the primary source of power for the Helmand and Kandahar provinces; protecting their lifespan and functionality is critical.”
“The new substation that we have installed will protect the hydroelectric generators, prolonging their life,” added Dietrick. “When there was a fault in the system in the past it would take an hour to get power back to that area. With the new substation it only takes 10 to 15 minutes to get power back. Fixing and restoring the major problems with the power plant has created stability and reliable infrastructure for the Afghan people.”