Current Recording; Variation Current Recording; Delta Current Recording; Residual Overcurrent Recording - ABB DRL6600U Product Manual

Disturbance Recording and Fault Locating Device DRL6600U
Product version: V8.30

5. Current recording

Variation current recording

When the power system is disturbed for some reason
(such as closing a circuit breaker, clearing a
disturbance, or load shedding), the magnitude and
phase of voltage and current may change over time,
which indicates that power system oscillation occurs.
The recorder can be triggered by the variation of
current in a time slot and record these power system
oscillation.

Delta current recording

For some industrial users, the load characteristic is
unstable. During normal operation, the voltage and
current can fluctuate significantly for a long term, under
which circumstance the load characteristic can be
recorded by the recorder for the user to analyze.

Residual overcurrent recording

By using residual current as an operation criterion, it's
possible to show the inrush process of transformer
energization. A large 3I
imbalance in the grid as well, which can be used to
monitor open phase operation on the line.
8
reflects a three-phase
0

6. Phase voltage recording

Overvoltage recording

When supplying power over an underground cable or a
network with high capacitance, the phase-to-ground
capacitance of the line may contribute to a voltage rise
(Ferranti effect). Long term operation may pose a threat
to the safety of energized equipment. Thus it's
necessary to monitor the voltage in the power system.

Delta voltage recording

Large-scale electrical equipment and conversion loads
connected to the grid are frequently powered off and
on. A voltage fluctuation will occur when large motors
are started or when large transformer are energized,
during which the recorder can record the voltage
fluctuations for users to analyze.
Third-, fifth-, and seventh-harmonic
overvoltage recording
Severe harmonic pollution effects the normal operation
of electrical equipment, and can damage the power
system. It can lead to capacitor damage due to thermal
overload and insulation breakdown and cause
electrical machine instability. Current and voltage
harmonics in transformers increase copper and iron
losses and in turn causes the temperature to rise,
affecting the insulation and decreasing the overload
capacity margin. Because harmonics also produce
resonance and noise, it's extremely important to record
and analyze harmonics in all segments of the power
system.
4CAE000359
Issued: May 2017
Revision: -
ABB