Active Series Compensator:
- These are one of the new technologies using power electronic component that can boost the voltage by injecting a voltage in series with the remaining voltage during a voltage sag condition.
- They are available in size ranges from small single-phase devices (1 to 5 kVA) to very large devices that can be applied on the medium-voltage systems (2 MVA and larger).
- When a disturbance to the input voltage is detected, a fast switch opens and the power is supplied through the series-connected electronics.
- This circuit adds or subtracts a voltage signal to the input voltage so that the output voltage remains within a specified tolerance during the disturbance.
- The switch is very fast so that the disturbance seen by the load is less than a quarter cycle in duration. This is fast enough to avoid problems with almost all sensitive loads.
- The circuit can provide voltage boosting of about 50 percent, which is sufficient for almost all voltage sag conditions.
Super Conducting Magnetic Energy Storage (SMES) Device:
- An SMES is a device, which can be used to Calibrate Voltage Sag and brief interruptions.
- The energy storage in a SMES based system is provided by the electrical energy stored.
- Since, the coil is lossless, the energy can be released almost instantaneously through the voltage regulator and inverter bank.
- This energy can be injected into the protected electrical system to compensate for the missing voltage during a voltage sag event.
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