| 摘要 |
An apparatus for self-diagnosing a disconnection in a secondary coil for a current transformer for a wattmeter is provided to prevent a wire disconnection due to the disconnection of the secondary coil by notifying a remote operator of the disconnection state of the current transformer. A relay driver(5) is added to an output terminal of a controller and activates a relay in response to an output signal from a controller. A relay(6) couples a movable terminal of a contact switch with an open fixing terminal, when a driving signal is outputted from the relay driver, and couples one end of a secondary coil with an input terminal of a coil state detector. A secondary coil state detector(4) is connected between the open fixed terminal and the input terminal of the controller and detects a current flow on the secondary coil, when the movable terminal is connected to the open fixed terminal. The controller(3) detects the current flowing in the secondary coil and drives the relay, when no current is introduced to the secondary coil for a predetermined time interval by using the relay driver. The controller receives an output signal from the secondary coil state detector and determines a disconnection state of the secondary coil. An alarm unit notifies the disconnection state of the secondary coil to a power management operator. |
