Calculating Settings For Instantaneous Phase Overcurrent Protection, Hv-Side, Phpioc - ABB Relion 650 Series Applications Manual

1MRK 504 124-UEN B
1. Set
To relate the settings to the rated data of the transformer the (HV) winding data should
be related to Global base 1
2. Set
*************************************
Range : 5 % to 50 % rated current
Step : 1 % transformer rated current
IEC98000017 V3 EN-US
Figure 13:
The operate characteristic is shown in figure 13. The only setting to be made is to set
IdMin . The default value is 30 % of IBase . This setting is recommended.
3.1.5 Calculating settings for instantaneous phase overcurrent
protection, HV-side, PHPIOC
1. Set
To relate the settings to the rated data of the transformer the (HV) winding data should
be related to Global base 1.
2. Set
The instantaneous phase overcurrent protection on the high voltage side is used for fast
trip of high current transformer internal faults. The protection shall be selective to the
protections of the outgoing 22 kV feeders. Therefore the maximum 145 kV current at
three-phase short circuit on the 22 kV side of the transformer is calculated:
I
GUID-662F8080-2FA3-47D9-B030-CDB4D502DB53 V2 EN-US
The dynamic overreach, due to fault current DC-component, shall be considered in the
setting. This factor is less that 5 %. The setting is chosen with a safety margin of 1.2:
I
set
Transformer protection RET650
Application manual
GlobalBaseSel to 1 .
IdMin to 30 % of IBase
operate current in pu
Base Sensitivity Idmin
minimum base sensitivity 50 %
default base sensitivity 30 %
maximum base sensitivity 5 %
Restricted earth fault protection trip characteristic
GlobalBaseSel to 1
IP>> to 1000 % of IBase
145
= =
× +
3 ( Z Z )
net T
×
3 (3.5
≥ 1.2 · 1.05 · 1 830 = 2 306 A
© Copyright 2011 ABB Power Grids. All rights reserved
5
4
operate
3
2
zone 1 zone 2
1
first slope
0 1 2
1.25 pu
145
=
1.83 kA
2
145
+ ×
0.12)
60
RET650 setting examples
second slope
block
3 4 5 6
bias current in per unit
IEC98000017-2-en.vsd
GUID-BE93278F-1769-42F1-992C-FEC0C964A88A v2
Section 3
(Equation 5)
39