Due to the unexpected national heat wave, peak demand for September 15 was rapidly increased more than the forecasted demand by about 5,000MW
* Forecasted peak demand for the day : 64,000MW
* Actual peak demand for the day : 69,060MW
(before taking emergency measures)
* Peak demand on Sept. 14 : 58,754MW
* Highest temperature nationwide on Sept. 15 : Seoul 30.8℃, Daejun 30.6℃,
Daegu 33.4℃, Gwangju 32.8℃, Pusan 30.7℃
Responding to high demand, pumped hydro was operated to its maximum and DSM was implemented including voluntary saving of 950MW. However, as we ran out of most of pumped hydro operating capacity, pumped hydro plant stopped operating one by one and it caused system frequency decreasing. At that time, there was a concern of massive blackout. If low frequency continued, it would cause a generator to be tripped, which could be spread to massive blackout.
It spite of taking all the countermeasures, KPX had no choice but to activate intentional load shedding as power demand continuously increased even after 14:30. After taking emergency load shedding, reserve margin was recovered to the level over 4000MW and the intentional load shedding was over at 20:00.