Setting Notes - Siemens 7SC80 Manual

Direction Determination of Directional Ground Element with Negative Sequence Values
Figure 2-34 shows the treatment of the reference voltage for the directional ground element using the nega-
tive sequence values based on a single-phase ground fault in phase A. As reference voltage, the negative
sequence voltage is used, as current for the direction determination, the negative sequence system in which
the fault current is displayed. The fault current -3Ι
the voltage 3V
2
TION ANGLE. In this case, a rotation of -45°.
[7sj6x_drehung-referenzspannung-erde-gegensys-220904-he, 1, en_US]
Figure 2-34
The forward area is a range of ±86° around the rotated reference voltage V
sequence system current -3Ι

Setting Notes

2.3.10
General
When selecting the directional time overcurrent protection in DIGSI, a dialog box appears with several tabs for
setting the associated parameters. Depending on the functional scope specified during configuration of the
protective functions in addresses 115 67/67-TOC and 116 67N/67N-TOC, the number of tabs can vary.
When setting address Address 116 67N/67N-TOC = Definite Time, only the parameters for definite time
overcurrent protection are accessible here. When selecting TOC IEC or TOC ANSI or Recloser Curves or
User Defined PU, the inverse time characteristics are additionally available.
At address 1501 FCT 67/67-TOC, directional phase overcurrent protection may be switched ON or OFF.
Pickup values, time delays, and characteristic are set separately for phase protection and ground protection.
Because of this, relay coordination for ground faults is independent of relay coordination for phase faults, and
more sensitive settings can often be applied to directional ground protection. Thus, at address 1601 FCT
67N/67N-TOC, directional ground time overcurrent protection may be switched ON or OFF independent of
the directional phase time overcurrent protection.
Depending on the parameter 613 Gnd O/Cprot. w., the device can either operate using measured values
or the quantities 3Ι0 calculated from the three phase currents. Devices featuring a sensitive ground current
Ι
N
input generally use the calculated quantity 3Ι0
The directional orientation of the function is influenced by parameter 201 CT Starpoint (see Section
2.1.3 Power System Data
Measurement Methods
The comparison values to be used for the respective element can be set in the setting sheets for the elements.
•
Measurement of the Fundamental Harmonic (standard method):
This measurement method processes the sampled values of the current and filters in numerical order the
fundamental harmonic so that the higher harmonics or transient peak currents are rejected.
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
by the fault angle ϕ . The reference voltage is rotated through the setting value 1619 ROTA-
sc
Rotation of the reference voltage, directional ground element with negative sequence values
is in this area, the device detects forward direction.
2
1).
2.3 Directional Overcurrent Protection 67, 67N
is in phase opposition to the fault current Ι
2
ref, rot
Functions
and follows
scA
. If the vector of the negative
125