Method and apparatus for monitoring power transmission
An apparatus ( 10 ) for measurement of power in an electric power transmission line ( 20 ) is disclosed. The apparatus ( 10 ) comprises a magnetic field sensor ( 30 ) for measuring the magnetic field ( 35 ) at the electric power transmission line ( 20 ) and transmitting magnetic field data ( 37 ) to a processor ( 40 ). The magnetic field sensor ( 30 ) is arranged at a minimum threshold distance from the electric power transmission line ( 20 ). The apparatus ( 10 ) also has a voltage sensor ( 50 ) arranged distally from the magnetic field sensor ( 30 ) for transmitting voltage waveform data ( 55 ) to the processor ( 40 ) and a transfer function calculator ( 60 ) for calculating the relationship between the transmitted voltage waveform data at the voltage sensor ( 50 ) and transmission line voltage waveform data ( 55 ).
1. An apparatus for determining power flowing in an electric high power transmission line in a power network comprising:
a processor;
a magnetic field sensor configured to measure in real time a magnetic flux in a magnetic field produced by a current flowing in the electric high power transmission line in the power network and to output a voltage signal proportional to a change in the measured magnetic flux, said magnetic field sensor further being configured to convert said outputted voltage signal into digital field data and to transmit the digital field data to the processor, wherein the magnetic field sensor is arranged within 400 meters of but at a distance from the electric high power transmission line;
a voltage sensor connected to a low voltage part of the power network remote from the electric high power transmission line for making a measurement associated with a voltage waveform in the low voltage part of the power network to create voltage waveform data and for transmitting the voltage waveform data to the processor;
a clock for sending time tag data to the magnetic field sensor, the voltage sensor and the processor; and
a power grid transfer function calculator configured to calculate a relationship between the digital field data and the voltage waveform data using an adjustment table;
wherein the processor is configured to calculate the power flowing in the electric high power transmission line from the digital field data, the voltage waveform data and the relationship between the digital field data and the voltage waveform data by accessing the transfer function calculator.
2. The apparatus of claim 1 , wherein the transfer function calculator comprises a look-up table.
3. The apparatus of claim 2 , wherein the look-up table stores constant values.
4. The apparatus of claim 1 , wherein the transfer function calculator calculates the relationship by differences in periods.
5. The apparatus of claim 1 , wherein the transfer function calculator comprises an algorithm.