A digital safety control system for monitoring and controlling leakage current and/or stray current on an electric path from a power-supply side of power receiving and transforming equipment to a plurality of loads, the power receiving and transforming equipment including a transformer for step-down distribution, the digital safety control system comprising:
- a transformer detection temperature value acquisition unit that is disposed for the transformer for step-down distribution disposed in the power receiving and transforming equipment and acquires a transformer detection temperature value TT° C. that is a temperature of the transformer;
- an instantaneous current value acquisition unit that acquires an instantaneous alternating current value or an instantaneous direct current value that is an instantaneous current value i (amperes) of a current flowing in an instantaneous time in an electric path in electrical equipment that is disposed on the electric path after stepping down with the transformer in the power receiving and transforming equipment;
- a transformer temperature determination unit that compares the transformer detection temperature value TT° C. with an allowable temperature range that is set in advance for a heat resistance class classified according to a heat resistance characteristic of an insulating material used in the transformer from which the transformer detection temperature value TT° C. has been grasped;
- an instantaneous current value determination unit that compares the detected instantaneous current value i (amperes) with an allowable current value range that is set in advance for the electric path in the electrical equipment from which the instantaneous current value i (amperes) has been acquired by the instantaneous current value acquisition unit;
- a notification information transmission unit that outputs notification information to an administrator terminal used by an administrator who manages the power receiving and transforming equipment and/or an operator terminal used by an operator who is in charge of managing the power receiving and transforming equipment;
- a notification information level determination unit that determines a level of the notification information output by the notification information transmission unit, based on a comparison result by the transformer temperature determination unit and a comparison result by the instantaneous current value determination unit;
- and
- a power-supply automatic interruptibility determination unit, a first power supply interruption unit, and a second power supply interruption unit, wherein
- the notification information level determination unit
- determines that a level of the notification information is caution notification information, when a comparison result by the transformer temperature determination unit indicates that the transformer detection temperature value TT° C. has reached a caution trigger temperature within the allowable temperature range, and a comparison result by the instantaneous current value determination unit indicates that a caution trigger current value within the allowable current value range has not been reached,
- determines that a level of the notification information is the caution notification information, when a comparison result by the transformer temperature determination unit indicates that the transformer detection temperature value TT° C. has not reached a caution trigger temperature within the allowable temperature range, and a comparison result by the instantaneous current value determination unit indicates that a caution trigger current value within the allowable current value range has been reached,
- determines that a level of the notification information is alert notification information that is the notification information of a type different from the caution notification information, when a comparison result by the transformer temperature determination unit indicates that the transformer detection temperature value TT° C. has reached a caution trigger temperature within the allowable temperature range, and a comparison result by the instantaneous current value determination unit indicates that a caution trigger current value within the allowable current value range has been reached, and
- determines that a level of the notification information is the alert notification information, when a comparison result by the transformer temperature determination unit indicates that the transformer detection temperature value TT° C. has reached an alert trigger temperature that is a temperature value higher than the caution trigger temperature within the allowable temperature range, or when a comparison result by the instantaneous current value determination unit indicates that an alert trigger current value that is a current value higher than the caution trigger current value within the allowable current value range has been reached,
- the notification information transmission unit outputs the notification information with the level determined by the notification information level determination unit,
- when the notification information level determination unit determines that a level of the notification information is the alert notification information, the power-supply automatic interruptibility determination unit determines whether a load is an automatically interruptible power supply load, for each of a plurality of the loads to which a current is supplied via the electrical equipment that is subjected to comparison by the instantaneous current value determination unit and from which the instantaneous current value i (amperes) has been acquired by the instantaneous current value acquisition unit,
- the first power supply interruption unit automatically interrupts power supply to the load determined as an automatically interruptible power supply load by the power-supply automatic interruptibility determination unit, and
- the second power supply interruption unit interrupts power supply to a load device controller controlling the load determined as not being an automatically interruptible power supply load by the power-supply automatic interruptibility determination unit, and then automatically interrupts power supply to the load.