Registration Systems in the Transmission Systems
Most fault recorders are installed in the switchgears for transmission systems. Even though the main applica-
tion area is still post-mortem analysis and thus the use of the Fast-scan recorder function, the use of other
functions to understand stability problems in the energy network and take the appropriate counter measures
is growing.
•
Capacitor voltage dividers are used in several transmission systems. In the case of a short circuit in the
line, high-frequency fault signals can occur in the voltage map, which then lead to over or under function
of protection devices. With the use of the function Fast-scan recorder, these transient processes, as well
as the behavior of the protection devices can be extensively analyzed.
•
Common-mode reactors at the beginning and end of transmission lines form a resonant circuit with the
line capacity and /or with a longitudinal condenser. If a line is shut off, then resonant oscillations can
exist, which last several network periods. For 1-pole short interruptions, these oscillations of the meas-
ured values of protection devices can be significantly corrupted and thus cause unwanted tripping. For
this reason the resonant oscillations must be recorded and analyzed after switching off the lines with the
function Fast-scan recorder.
•
Inductance of voltage transformers and scatter capacities in switchgears (busbars, lines) can lead to
ferroresonance effects. These problems are not registered under normal conditions of protection devices.
If these problems are not detected and counter measures implemented in a timely manner, significant
damage can result in the switchgear, such as the explosion of voltage transformers. For registration of
these processes, the function Fast-scan recorder is necessary.
•
Measurements over large areas of the transmission system (Wide Area Monitoring) can be performed
with the functions Slow-scan recorder and Phasor Measurement Unit (PMU). The objective of the
measurements is the detection of power fluctuations and power swing cycles as well as voltage and
frequency stability problems.
•
Increasingly, the use of continuous recorders is growing. With these functions, the long-term stability
problems can be analyzed in detail. These measurements form a solid foundation for expensive invest-
ments such as the procurement of compensation systems (SVC).
•
The availability and quality of the power supply is very important for power distribution utilities. To
monitor the voltage quality (also known as Power Quality (PQ)) over a long period of time, the Trend
recorder function must be used. With this function, the long-term behavior of voltages (fluctuations in
frequency, voltage, short-term voltage changes, transients, signal distortions, etc.) can be precisely
recorded. Using the Trend recorder function contributes to a high-quality and reliable energy supply. An
analysis according to EN 50160 can be mapped using the averaged values (frequency: 10 s; short-term
flicker strength over 10 minutes and long-term flicker strength over 2 hours).
Registration Systems in HVDC Switchgear
The use of modern registration systems in high-voltage DC transmission systems (HVDC) is significantly
different than the use in transmission systems or power plants.
The use of the classic function Fast-scan recorder is thus very important in connection with the process signal
inputs. With this constellation, it is possible to register alternating and direct-voltage variables together. In
some cases, it is additionally desired to register gate trigger pulses for thyristors via binary channels. Areas of
use are, for example, Flexible Alternating-Current Transmission Systems (FACTS) and thyristor-driven reactive-
power compensation systems.
In the future, it can be expected that, in HVDC and FACTS systems, the use of the functions Slow-scan
recorder, Continuous recorder and Phasor Measurement Unit (PMU) will increase to monitor the function
groups of the system for stability control of the network and to register faults.
Registration Systems in Distribution Systems and Industrial Complexes
Modern registration systems are used in important transformer stations where the transition from transmis-
sion to distribution takes place. Such transformer stations are present both in the power utility area as well as
in industrial complexes. The most important function is here the Fast-scan recorder for registering short
circuits.
Introduction
1.5 Scope of Functions
SIPROTEC 5, Fault Recorder, Manual 29
C53000-G5040-C018-5, Edition 11.2017
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