Abstract: A method and apparatus for measuring quantities of a multi-phase electric line, the apparatus comprising a control unit and a measurement unit in connection with each phase conductor of the electric line, wherein each measurement unit is arranged to measure a first phase quantity of the phase conductor in connection with which it is located and to transfer the measured quantity value to the control unit, the measurement unit located in connection with one phase conductor being further arranged to measure phase angles between the first phase quantity of said phase conductor and first phase quantities of other phase conductors and to transfer the measured phase angle values to the control unit.

Abstract: A power supply arrangement, especially in connection with a conductor (5) of a medium-voltage overhead line, which arrangement comprises a power supply (2) and a first and second element (3, 4) made of an electrically conductive material, which are connected electrically to the power supply for feeding energy to the power supply. The first element (3) of the power supply arrangement is arranged to be close to the conductor (5) and has a capacitance (Ce) to an element in a second potential, the capacitance being arranged to charge itself by effect of an electric field generated by the voltage of the medium-voltage conductor, and said second element (4) is arranged to have a galvanic or capacitive connection with the conductor (5) for feeding energy to the power supply (2) from the potential difference between said first and second elements.

Abstract: A power supply arrangement, especially in connection with a conductor (5) of a medium-voltage overhead line, which arrangement comprises a power supply (2) and a first and second element (3, 4) made of an electrically conductive material, which are connected electrically to the power supply for feeding energy to the power supply. The first element (3) of the power supply arrangement is arranged to be close to the conductor (5) and has a capacitance (Ce) to an element in a second potential, the capacitance being arranged to charge itself by effect of an electric field generated by the voltage of the medium-voltage conductor, and said second element (4) is arranged to have a galvanic or capacitive connection with the conductor (5) for feeding energy to the power supply (2) from the potential difference between said first and second elements.

Abstract: A method and apparatus for measuring quantities of a multi-phase electric line, the apparatus comprising a control unit (7) and a measurement unit (4, 5, 6) in connection with each phase conductor (1, 2, 3) of the electric line, wherein each measurement unit is arranged to measure a first phase quantity of the phase conductor in connection with which it is located and to transfer the measured quantity value to the control unit (7), the measurement unit located in connection with one phase conductor being further arranged to measure phase angles between the first phase quantity of said phase conductor and first phase quantities of other phase conductors and to transfer the measured phase angle values to the control unit (7).