Abstract: According to an embodiment, a fault point location method of locating a fault point by using a voltage and a current of each terminal of a transmission line to be located and a transmission line constant is disclosed. According to the method, a formula simplified by a secondary approximation using an approximation of a hyperbolic function from a basic equation of a distributed constant circuit equation using the hyperbolic function or a formula simplified by a division of both sides by the hyperbolic function is determined. A location distance from a predetermined end of the transmission line to the fault point is calculated by using the simplified formula.

Abstract: A method for fault location is provided which can accurately perform a fault location process by a simple and direct calculation without requiring no synchronization of terminals. Data relating to the voltage and the current (vector quantity) at opposite ends of a power transmission line section to be located and a transmission line constant set in advance are used. When the distance x from a designated terminal A to a fault point F is an unknown quantity, the distance x can be calculated by solving a quadratic equation obtained by taking as the fault point a point where values of the second power of a fault point voltage in a fault phase when viewed from opposite ends of the section to be located are equal to each other.

Abstract: The present invention provides a wide area protection control measurement system and method which excels in economy, reliability and expandability, in which applied arithmetic operation functions for protection, control and measurement can be freely added and changed, without adding or changing power monitoring terminals to be installed in the electric-supply station. The wide area protection control measurement system is configured from N number of power monitoring terminals 1 installed in an electric-supply station in a target range, one electric quantity aggregation device 3 connected with these power monitoring terminals 1 via a communication network 2, and M number of applied arithmetic operation devices 4 connected with the electric aggregation device 3 through an inter-device connection. Each power monitoring terminal 1 transmits electric quantity data to the electric quantity aggregation device 3 via the communication network 2.

Abstract: The present invention provides a wide area protection control measurement system and method which excels in economy, reliability and expandability, in which applied arithmetic operation functions for protection, control and measurement can be freely added and changed, without adding or changing power monitoring terminals to be installed in the electric-supply station. The wide area protection control measurement system is configured from N number of power monitoring terminals 1 installed in an electric-supply station in a target range, one electric quantity aggregation device 3 connected with these power monitoring terminals 1 via a communication network 2, and M number of applied arithmetic operation devices 4 connected with the electric aggregation device 3 through an inter-device connection. Each power monitoring terminal 1 transmits electric quantity data to the electric quantity aggregation device 3 via the communication network 2.

Abstract: A protection relay for determining whether or not a fault point of a power system exists in a predetermined range including a filter section for inputting sampling data of a voltage and a current in the power system to a digital filter having a predetermined transfer function and outputting a first voltage data and a first current data, and a second voltage data and a second current data normal to the first voltage data and the first current data, respectively, a calculator for calculating a predetermined measurement value based on the first and second voltage data, and the first and second current data at a first time and the first and second voltage data, and the first and second current data at a second time different from the first time, and an operation decision section for performing an operation decision based on the predetermined measurement value obtained by the calculator.

Abstract: A protection relay for determining whether or not a faultal point of a power system exists in a predetermined range, comprises filter section for inputting sampling data of a voltage and a current in the power system to a digital filter having a predetermined transfer function and outputting a first voltage data and a first current data, and a second voltage data and a second current data normal to the first voltage data and the first current data, respectively, calculator for calculating a predetermined measurement value based on the first and second voltage data, and the first and second current data at a first time and the first and second voltage data, and the first and second current data at a second time different from the first time, and operation decision section for performing an operation decision based on the predetermined measurement value obtained by the calculator.