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tion is possible as well). The 4th voltage input is for displacement voltage measure-
ment for stator earth fault protection.
The IA input amplifier group allows high impedance connection for analog input values
and contains filters optimized for measured value processing bandwidth and speed.
The AD analog digital converter group contains high resolution Σ∆ digital converters
(22 bits) and memory components for data transfer to the microcomputer.
Microcomputer
The implemented software is processed in the microcomputer system (µC). Essential
System
functions are:
• Filtering and conditioning of the measured signals,
• Continuous monitoring of the measured quantities
• Monitoring of the pickup conditions for the individual protective functions
• Querying of limit values and time sequences,
• Control of signals for logical functions,
• Decision for trip commands
• Signalling of protection behaviour via LEDs, LCD, relays or serial interfaces
• Storage of indications, fault data and fault values for fault analysis,
• Management of the operating system and its associated functions such as data re-
Adaptation of Sam-
The frequency of the measured quantities is continuously measured and used for ad-
pling Frequency
justing of the actual sampling frequency. This ensures that the protection and mea-
surement functions produce correct results over a wide frequency range. This ensures
measuring accuracy in the frequency range from 11 Hz to 69 Hz.
The sampling frequency adaptation can, however, operate only when at least one a.c.
measured quantity is present at one of the analog inputs, with an amplitude of at least
5 % of rated value ("operational condition 1").
If no suitable measured values are present, or if the frequency is below 11 Hz or above
70 Hz, the device operates in mode "operational condition 0".
Binary Inputs and
Binary inputs and outputs from and to the computer system are routed via the I/O
Outputs
modules (inputs and outputs). The computer system obtains the information from the
system (e.g remote resetting) or the external equipment (e.g. blocking commands).
Outputs are mainly commands that are issued to the switching devices and messages
for remote signalling of events and states.
Front Elements
Optical indicators (LEDs) and a front display panel (LC display) provide information on
the function of the device and indicate events, states and measured values. Integrat-
ed control and numeric keys in conjunction with the LCD facilitate local interaction with
the device. By this means all information on the device such as design and setting pa-
rameters, operation and disturbance indications and measured values can be queried,
(see also SIPROTEC
changed.
7UM61 Manual
C53000-G1176-C127-3
cording, real-time clock, communication, interfaces, etc.
®
System Description /1/), and setting parameters can be
1.1 Overall Operation
19
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