Abstract: According to one embodiment, a method is used for diagnosing a deterioration of a utility pole having at least one bolt and a plurality of holes provided for attaching the bolt. In the method, an impact is applied to the bolt. Elastic waves generated due to the impact are detected by a sensor shaped like a bolt. The sensor is attached to at least one of the holes. A propagation situation of the elastic waves in the utility pole is derived, based on the elastic waves detected, and each position of the bolt and the sensor.

Abstract: According to one embodiment, a method is used for diagnosing a deterioration of a utility pole having at least one bolt and a plurality of holes provided for attaching the bolt. In the method, an impact is applied to the bolt. Elastic waves generated due to the impact are detected by a sensor shaped like a bolt. The sensor is attached to at least one of the holes. A propagation situation of the elastic waves in the utility pole is derived, based on the elastic waves detected, and each position of the bolt and the sensor.

Abstract: A protective relay system includes plural protective relay devices protecting a power system based on electrical quantity data from the power system, and a communication between the protective power devices is performed via a network. The protective relay device includes a clock unit periodically clocking a timing at which sampling is performed on an electrical quantity of the power system, a relay computing unit performing a relay computation based on the electrical quantity data having undergone the sampling and electrical quantity data received via the network, a random-number creating unit creating a random number, and a synchronization-frame processing unit setting a timing of sending a synchronization frame to another protective relay device via the network based on the random number created by the random-number creating unit.

Abstract: A protective relay system inducting includes plural protective relay devices protecting a power system based on electrical quantity data from the power system, and a communication between the protective power devices is performed via a network. The protective relay device includes a clock unit periodically clocking a timing at which sampling is performed on an electrical quantity of the power system, a relay computing unit performing a relay computation based on the electrical quantity data having undergone the sampling and electrical quantity data received via the network, a random-number creating unit creating a random number, and a synchronization-frame processing unit setting a timing of sending a synchronization frame to another protective relay device via the network based on the random number created by the random-number creating unit.

Abstract: According to one embodiment, there is provided an integration unit for protecting a power system from a failure includes an A/D converter configured to convert a quantity of electricity of a power system into digital data. The integration unit includes a communication interface unit configured to transmit the digital data to a process bus connected to a protection unit configured to protect the power system. The integration unit includes a relay calculation unit configured to execute a relay calculation operation to detect an abnormality of the power system based on the digital data and to output, based on the calculation operation result, a circuit breaking signal to trip and drive a circuit breaker inserted in the power system.

Abstract: A short-circuit distance relay is provided which has a high accuracy and an excellent reliability such that the relay can determine the fault phase based on impedance values measured by each phase, prevent misjudgment and unnecessary operation due to overreach without depending on the power system conditions, and operate even if multiple faults occur. An impedance calculation part (11) calculates an impedance value of the phase in which the direction element (SM) has operated. A minimum phase selection part (12) selects as a fault phase, the phase having a minimum impedance value. When the impedance value of the selected phase is equal to or less than the setting impedance value of the distance element of the phase, an output of the distance element of the phase is made to be valid to output an opening command to a circuit breaker. As a result, it is possible to prevent misjudgment and unnecessary operation due to overreach without depending on the power system conditions.