Mechanically switched capacitors (MSC/MSCDN) with optional filter circuit
In many cases, the simplest solution for controlling reactive power is just sufficient. That makes mechanically switched capacitors (MSC) and mechanically switched reactors (MSR) the most economical power compensation devices for mainly constant or predictable voltage. Both devices are connected to the grid via high-voltage circuit breakers. Under heavy load conditions, MSCs provide voltage control and grid stabilization in a simple and cost-efficient way. MSRs provide stability under low load conditions or can be used at the end of long, radial AC lines. However, usage is somewhat limited as the capacitors need to discharge for several minutes after switching off an MSC bank. Filter circuits are often used in industrial plants. The filter circuits damp the generated harmonics which are produced by inverters and nonlinear loads.
