ABB Remote I/O RIO600 Installation And Commissioning Manual page 119

1MRS757488 H
RIO600
Installation and Commissioning Manual
A modern approach to directional fault detection is the active or reactive current
measurement. The operating characteristic of the directional operation depends on the
earthing principle of the network. The Iosin(ϕ) criterion is used in an isolated network,
measuring the reactive component of the fault current caused by the earth capacitance.
The Iocos(ϕ) criterion is used in the compensated network, measuring the active
component of the fault current.
The operation criteria Iosin(ϕ) and Iocos(ϕ) are selected with the Operation mode
setting using the values "IoSin" or "IoCos" respectively.
When the Iosin(ϕ) or Iocos(ϕ) criterion is used, the component indicates a forward or
reverse-type fault through the STR DIRGENERAL output, where 1 = forward fault
and 2 = reverse fault.
In case of low magnitude, the STR DIRGENERAL output is set to 0 = unknown. The
function is allowed to operate in the directional mode as non-directional, since the
directional information is invalid.
The following examples show the characteristics of different operation criteria.
Example 1
If Iosin(ϕ) criterion is selected in forward-type fault, the STR DIRGENERAL = 1.
Section 6
Commissioning
111