The facts of nonobservance of interstate net power flow have been reported since the beginning of autumn and winter period 2010/2011 on the border between Kazakhstan Unified Power System (UPS) and Central Asia Integrated Power System (IPS).
On 5 January 2011 during evening peak hours the non-contractual power consumption (about 300 MW) by Uzbekistan was recorded. At 6:27 pm two out of three existing 220 kV lines connecting the coordinated hydro power plants (Kurpsay HPP, Tashkumyr HPP, Shamaldysai HPP and Uchkurgan HPP) were sequentially tripped in the power system of Kyrgyzstan.
At 6:37 pm (AST) the loss of generating capacity (up to 800 MW) in Central Asia IPS led to overload and tripping of North-South transit interconnection in Kazakhstan UPS. Thus, the information released by some media on transit separation due to severe cold is incorrect.
The process disturbance resulted in 436 MW load shedding for consumers in South Kazakhstan and 1287 MW for CA IPS (including Uzbekistan – 925 MW, Kyrgyzstan – 362 MW). Additionally the gas turbine units have been tripped in Kzylorda oblast at Kumkol Gas Turbine Power Plant in total capacity of 50 MW.
At 8:11 pm by virtue of measures taken by System Operator`s personnel the isolated Zone South of Kazakhstan UPS was synchronized with Zone North, at 8:56 pm the consumers of South Kazakhstan, Zhambyl and Kzylorda oblasts were connected, at 10:07 pm the power supply to consumers of Kazakhstan UPS was completely restored.
The beginning of 2011 confirmed anxiety of System Operator - KEGOC regarding possible negative consequences of unbalanced operation of Central Asia IPS. In order to provide reliable power supply to consumers of Kazakhstan UPS, the System operator decided to activate earlier developed technical arrangements to separate the Kazakhstan power system from Central Asia IPS at the accountability border.