GE L90 User Manual

CHAPTER 2: PRODUCT DESCRIPTION SIGNAL PROCESSING
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 2-29
2
Figure 2-4: UR signal processing
The UR samples its AC signals at 64 samples per cycle, that is, at 3840 Hz in 60 Hz systems, and 3200 Hz in 50 Hz systems.
The sampling rate is dynamically adjusted to the actual system frequency by an accurate and fast frequency tracking
system.
The A/D converter has the following ranges of AC signals:
Voltages:
Eq. 2-1
Currents:
Eq. 2-2
Current harmonics are estimated based on raw samples with the use of the full-cycle Fourier filter. Harmonics 2nd through
25th are estimated.

GE L90 Specifications

General

Communication	Ethernet, Serial
Mounting	Panel Mount
Frequency	50/60 Hz
Inputs	Digital, Analog
Outputs	Relay
Control	Local, Remote
Communication Interface	IEC 61850, DNP3, Modbus
Protection Functions	Differential, Ground Fault
Standards Compliance	IEC, IEEE