Control of a power transmission system

A power control device for providing improved control of a power transmission system, said system having a first group of measurement units in a first geographical area and providing a first set of on-line measured phasors and a second group of measurement units in a second geographical area and providing a second set of on-line measured phasors, where the first and second groups of measurement units each include at least two measurement units and the phasors in the first and second sets are generated at the same instant in time, said power control device being configured to obtain the first set of phasors from the first group of measurement units and the second set of phasors from the second group of measurement units, the device further comprising:

• a phasor aligning unit configured to align the first and second sets of phasors with each other in time, and
• a control unit configured to compare the number of phasors in each set of phasors with a corresponding phasor minimum number threshold, determine that a first control condition is fulfilled if each such phasor number threshold has been exceeded and enable the provision of a control signal if at least said first control condition is fulfilled, where this control signal is based on said obtained phasors in the first and second sets and provided for use in inter-area oscillation damping in relation to the first and the second geographical areas.

A non-transitory machine-readable storage medium comprising a computer program for providing improved control of a power transmission system having a first group of measurement units in a first geographical area and providing a first set of on-line measured phasors and a second group of measurement units in a second geographical area and providing a second set of on-line measured phasors, where the first and the second groups of measurement units each include at least two measurement units and the phasors in the first and second sets are generated at the same instant in time, the computer program being loadable into an internal memory of a power control device and comprises computer program code means to make the power control device, when said program is loaded in said internal memory,

• obtain the first set of phasors from the first group of measurement units and the second set of phasors from the second group of measurement units aligned with each other in time,
• align the first and second sets of phasors with each other in time,
• compare the number of phasors in each set of phasors with a corresponding phasor minimum number threshold,
• determine that a first control condition is fulfilled if each such phasor number threshold has been exceeded, and
• enable the provision of a control signal based on said obtained phasors in the first and second sets if at least said at least said first control condition is fulfilled where this control signal is provided for use in inter-area oscillation damping in relation to the first and the second geographical areas.