The Korean power system is unique in terms of power demand and generation. Almost 40% of its power demand of the country is in the metropolitan area of the country. Due to its "remote" generation site, the network is highly susceptible to voltage drop...
The Korean power system is unique in terms of power demand and generation. Almost 40% of its power demand of the country is in the metropolitan area of the country. Due to its "remote" generation site, the network is highly susceptible to voltage drop and power losses along the network when the load levels are medium. And the network is also susceptible to transient & dynamic stability problems because of potential deficit of reactive power nearby. With the low load it became increasingly difficult to maintain voltage levels where they considered to be generated from ultra High voltage & underground cable transmissions.
Therefore, reactive power control methodology and strategic plans must be established. From switching, contingency and fault studios conducted for the metropolitan area and neighboring network. The assessment on the reserve ratio, capacity required and the required voltage preservation levels were also conducted. This included detail voltage stability and reactive power margins studies to determine the required spinning reserve reactive power rates.
The contingency and fault studies conducted for the year 2004 and 2007 of the peak loads. The rating capacity of active/reactive power was verified by performing a number of contingencies on the 765kV Shingapyeong-Shintaebaek and Shinansung-Shinseosan transmission lines using P-V & Q-V curves. In case of those peak loads simulation cases, it was clear that the network was susceptible to transient & dynamic stability problems because of shortage of reactive power nearby areas. This would make the power system inoperable unless very effective, fast and extremely reliable countermeasures were taken. With the analysis of reactive power sources' characteristics, we concluded that the solution to the fault was the installation of a very fast Mvar compensator. Based on these simulation results, we could come up with the required capacity of spinning reserve reactive power.