ABB Remote I/O RIO600 Installation And Commissioning Manual page 131

1MRS757488 H
RIO600
Installation and Commissioning Manual
harmonic components are present in the fault quantities, they turn the phasor
align to the negative Im(
• Phasor 2 depicts the direction of accumulated sum admittance phasor in case of
an earth fault inside the protected feeder when the network is unearthed. The
result is also valid in compensated networks when there are harmonic
components present in the fault quantities (typically low ohmic permanent or
intermittent fault). In this case, the result is valid regardless of the network's
actual compensation degree. Harmonics turn the phasor align to the positive
Im( ) axis.
Y
o
• Phasors 3 and 4 depict the direction of accumulated sum admittance phasor in
case of a higher-ohmic earth fault in the protected feeder without harmonics in the
fault quantities when the network is compensated. As no harmonic components
are present, the phase angle of the accumulated phasor is determined by the
compensation degree of the network. With high degree of overcompensation, the
phasor turns towards the negative Im(
The characteristic Tilt angle should reflect the measurement errors,
that is, the larger the measurement errors, the larger the Tilt angle
setting should be. Typical setting value of 10 degrees is
recommended.
The detected fault direction is available as GOOSE outputs MFAPSDE_OpFw and
MFAPSDE_OpRe. Outputs MFAPSDE_OpFw and MFAPSDE_OpRe provide the
fault direction irrespective of settings Power direction logic and Directional mode.
To adapt the fault direction determination to possible fault direction change during the
fault, for example, during manual fault location process, a cyclic accumulation of sum
admittance phasors is conducted. The duration of this directional evaluation cycle is
1.2 ⋅ Reset delay time (minimum of 600 ms). If the fault direction based on the cyclic
phasor accumulation is opposite to the function direction output for Reset delay time
or 500 ms (minimum of 500 ms), the function is reset and fault direction calculation
of MFAPSDE is restarted.
The direction of the MFAPSDE function is supervised by a settable current magnitude
threshold. The operate current used in the magnitude supervision is measured with a
special filtering method, which provides very stable residual current estimate
regardless of the fault type. This stabilized current estimate is the result from
fundamental frequency admittance calculation utilizing the CPS technique. The
stabilized current value is obtained (after conversion) from the corresponding
admittance value by multiplying it with the system nominal phase-to-earth voltage
value (=1/sqrt(3) which is entered as Nominal voltage). The stabilized values of the
fundamental frequency admittance and the corresponding current are calculated with
Equation 16 and Equation
) axis.
Y
o
) axis (as phasor 4).
Y
o
17.
Section 6
Commissioning
123