The protection function can detect earth faults in the entire rotor winding and
associated connections.
Requires injection unit REX060 and a coupling capacitor unit REX061 for correct
operation.
7.8.3 Description of input signals
The inputs to the sensitive rotor earth-fault protection function block are as shown in
table 122.
Table 122: Description of various inputs
Input signal Description
USU The measured injection voltage. This signal is taken from a pre-processor block, the AI
output. The analog voltage input AI1 is linked to the phase L1 in the pre-processor block
in the Signal Matrix tool.
USI
The measured injection current. This signal is taken from a pre-processor block, the AI
output. In the pre-configured version, the analog voltage input AI2 is linked to the phase
L2 in the pre-processor block in the Signal Matrix tool.
BLOCK
Input to block the function
ZREFSEL The selection of any of the predefined reference impedances. There is a possibility to
change from one set reference impedance to another. Two different reference
impedances are available.
7.8.4 Description of output signals
The outputs of the sensitive rotor earth-fault protection function block are as shown in
table
123.
Table 123: Description of various outputs
Output signal
Description
TRIP Common trip command signal
TRIPDC is the trip command signal at DC-side earth fault
TRIPAC is the trip command signal at AC-side earth fault
START is a common signal for both AC and DC side of exciter
STARTDC is the start signal at DC-side earth fault
STARTAC is the start signal at AC-side earth fault
ALARM Signal activated after a set time delay, if the calculated fault resistance gets lower than
the set alarm level
ERROR Error signal which is boolean with values 0 and 1
ERRSTAT Status coded signal giving type of error. See table 124
RAVE Measured resistance to earth in Ω at an injected frequency (real part of the complex
impedance)
XAVE Measured reactance to earth in Ω at the injected frequency (imaginary part of the
complex impedance)
Table continues on next page
Section 7 1MRK502052-UEN B
Impedance protection
280
Technical manual
To Next Page
Loading...
