| 摘要 |
PROBLEM TO BE SOLVED: To prevent reactive power injected into a power system from being cancelled, to securely detect isolated operation even when the reactive power balances with load reactive power.SOLUTION: An isolated operation detection method includes: a first step of injecting reactive power to a power system; a second step of additionally injecting reactive power having a preset phase within a first period, when already injected reactive power has balanced with load reactive power; a third step of determining interference between the already injected reactive power and additionally injected reactive power, by using the absolute value of a difference between a value of a frequency deviation at the time of the additional injection at the second step and a value of a frequency deviation at the time at which a second period shorter than the first period has passed; a fourth step of further injecting additional injection reactive power having a phase obtained by reversing a phase of the additionally injected reactive power, when a result of the determination at the third step has shown interference; and a fifth step of continuing injection of additional reactive power having the same phase as the additionally injected reactive power injected at the second step during the remaining period until the first period has passed from the time of additional injection at the second step, when the result of the determination at the third step has shown non-interference.SELECTED DRAWING: Figure 5 |
