Shown at Left is a Medium Voltage breaker manufactured by ABB. Other manufacturers include Siemens and Eaton. Vacuum and SF6 breaker types are acceptable for use with the Dynamic VAR Systems.
Breakers must be properly rated for the power system characteristics and for the Dynamic VAR System Size.
The breaker is a switch designed to connect or disconnect power from the Dynamic VAR system. Breakers need to be operated - either manually or by a "smart" control. In order to exceed typical requirements T-Star recommends using two "smart" controls to operate the breaker.
The first smart control is the Dynamic VAR system controller discussed elsewhere. It should remove the Dynamic VAR system from power in event of irregularities.
The second smart control is the breaker relay. It backs up the Dynamic VAR controller and provides secondary control capabilities in event of problems such as current imbalances, high impedance faults and upstream power issues.
Together these ensure maximum effectiveness and safety.
Disconnect Switch: Medium Voltage is a highly dangerous environment. Prior to working on de-energized equipment, standard safety practices call for ensuring that the equipment is visibly disconnected and grounded to ensure worker safety.
Shown at left is a visible disconnect and isolation switch with grounding capability. Its one common way to provide isolation and grounding. Others include:
- Separate isolation and grounding switches
- A "rack-out" breaker that provides visible isolation and includes built-in grounding studs.