CHAPTER 5: SETTINGS
The phase directional element responds to the forward load current. In the case of a following reverse fault, the
element needs some time—in the order of 8 ms—to establish a blocking signal. Some protection elements, such as
instantaneous overcurrent, respond to reverse faults before the blocking signal is established. Therefore, a
coordination time of at least 10 ms must be added to all the instantaneous protection elements under the
supervision of the phase directional element. If current reversal is of concern, a longer delay—in the order of 20
ms—is needed.
5.7.8 Neutral current
5.7.8.1 Menu
SETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) NEUTRAL CURRENT
NEUTRAL CURRENT
T60 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 5-155: Phase directional logic
NEUTRAL TOC 1
NEUTRAL TOC 6
NEUTRAL IOC 1
NEUTRAL IOC 12
GROUPED ELEMENTS
See below
See page 5-277
5
5-275