Hitachi Relion 670 Series Applications Manual page 66

Section 4
Analog inputs
IL1
TRM_40.CH1(I)
IL2
TRM_40.CH2(I)
UL1L2
TRM_40.CH7(U)
2Uo
TRM_40.CH8(U)
IEC17000020 V1 EN-US
Figure 22:
In order to make the IED to work in such system, the following steps to be performed (see Figure 22):
1. Connect UL1L2 voltage to the third input of the SMAI
2. Connect one not used and externally not wired VT input on the RER670 TRM, with set ratio as
0.1kV/100V=1.00, to the fourth input of the SMAI function block. This in principle gives zero
value for 2Uo quantity.
3. Note that, in a rear case that 2Uo voltage is available from the two-phase power system then
just simply connect it to the second VT input on the TRM and set its ratio accordingly. In such
cases, all internal calculations will work correctly all the time.
When such configuration is made within ACT tool using three available analogue signals (i.e. UL1L2,
IL1 and IL2), the preprocessing block will perform the following:
• Quantities for the first phase and second phase currents (i.e. IL1 and IL2) will be directly
measured from the TRM
• Quantities for the first phase and second phase voltages (i.e. UL1 and UL2) will be calculated.
Because by such arrangement, the 2Uo is practically forced to zero, the two phase voltages will
be calculated correctly only during symmetrical operating condition in the network (i.e. without
any earth fault) using the following formulas UL1 = -UL2 = UL1L2/2
• Phase-to-phase current value (i.e. IL1L2 = (IL1-IL2) ) will be internally calculated
• Phase-to-phase voltage value (i.e. UL1L2 ) will be directly measured from the TRM
• Positive sequence quantities (i.e. U1 = (UL1-UL2)/2 and I1 = (IL1-IL2)/2 ) will be internally
calculated
• Zero sequence current quantity (i.e. 2Io = (IL1+IL2) ) will be internally calculated.
• Zero sequence voltage quantity (i.e. 2Uo ) will be directly measured from the TRM. However,
because this input is not wired and the ratio is set to value one, it will practically be forced to
zero value permanently.
Note that in such installations, distance or under-impedance protection can only use L1-L2
measurement loop which will then effectively measure impedance Z = UL1L2/(IL1-IL2). The
directional overcurrent protection can also be used. Directional earth fault protection and residual
overvoltage protection shall not be used in such installations. All other backup protection and
measurement functions can be used.
4.2.5.3 Configuration example 3
An example on how to configure the IED analogue inputs for single-phase railway supply systems or
BT-catenary railway supply systems is shown in Figure 23.
60
SMAI1
BLOCK G1AI2P
GRP1L1 G1AI1
GRP1L2 G1AI2
GRP1L1L2 G1AI3
G1AI4
GRP1N
G1N
O:1IT:3II:1
SMAI2
BLOCK G2AI2P
GRP2L1 G2AI1
GRP2L2 G2AI2
GRP2L1L2 G2AI3
GRP2N G2AI4
G2N
O:1IT:3II:2
Configuration for two-phase power system when only phase-to-phase voltage is
available
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ZGTPDIS
Trip
TRIP
I2P
Logic
TRZ1
U2P
BLOCK TRZ2
BLKZ TRZ3
START
BLKZ1
STZ1
BLKZ2
BLKZ3 STZ2
STZ3
O:920IT:3II:1
1MRK506375-UEN Rev. N
BOM_4.BO1
BOM_4.BO2
IEC17000020-1-en.vsd
GUID-09488ED6-BABD-4BCE-B4F2-F5539100308E v1
Railway application RER670
Application manual