GE MOV 2000, Инструкция по эксплуатации

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5. HARDWARE DESCRIPTION
36 MIV Digital Multifunctional Protective Relay GEK-106271
The terminal blocks situated on the rear of the case are identified with the letters A, B, C and D, and optionally E
and F, as shown in figure 6. In addition, each terminal is identified with a number.
The communications connectors are situated on left-hand side of the front and on the right-hand side of the rear of
the case. The front port is labelled as PORT 1 and the rear ports as PORT 2 and PORT3. The IRIG-B connection
is made using a block of two additional terminals.
5.2. OPERATION THEORY
The MOV unit measures voltage signals, carries out complex calculations using internal data, stores relevant
events, activates trip relays and generates information which can be used to determine the status of the power
system to which it is connected. The functionality of the MOV can be divided into the following sections :
- Magnetic module
- CPU board
- Power supply
- Keyboard and display
5.2.1. MAGNETIC MODULE
The magnetic module carries out two essential functions : galvanic insulation and scaling analog input signals. In
the case of voltage transformers it scales the input voltage so that internally the unit works with voltages which are
greatly below the input voltages. In the case of current transformers the input current for the primary winding is
converted into a scaled voltage in the secondary winding of the transformer. Each voltage and current transformer
must be linear in the whole measurement range of the relay. The voltages supplied by the input transformers are
applied directly to the CPU signal processing board.
5.2.2. CPU BOARD
The MOV uses two 16-bit microprocessors operating at a clock frequency of 20 MHz. One of these
microprocessors is used to carry out relay communications and the other to carry out the calculations which are
necessary for the protection functions. The microprocessor chosen is designed to carry out input and output
calculations and operations at very high speed. The use of two microprocessors is especially recommendable so
as to make the protection and communication functions totally independent of each other inside the unit itself, and
thereby increase the reliability of the system.
The analogue-digital converter converts the voltage inputs into their digital equivalent with a resolution of 10 bits.
The unit's code is stored in non-volatile EPROM memory while the settings and events are stored in non-volatile
EEPROM memory. The data related to the oscillography is stored in RAM memory which is maintained using a
capacitor, thus avoiding the loss of information when the unit is disconnected.
A high resolution real time clock is used to time-tag the events and ensure an appropriate post-fault analysis can
be done, with a resolution of one millisecond. This clock can be synchronised externally using an IRIG-B type
input.
The input and output functions are divided between the two microprocessors. The serial ports, the keyboard and
the display are controlled by the communications microprocessor. External communications are processed by a
serial communications controller circuit which contains a universal asynchronous transceiver (DUART). The digital
inputs and outputs are processed by the protection microprocessor.
The MOV contains 6 independent circuits to process digital inputs. These circuits check the presence or absence
of input voltage and are designed to insulate them electrically from the microprocessor, thus increasing the
reliability of the system.
On the front of the relay there is a set of 17 LEDs, one of which is fixed and indicates the operating status of the
unit, and the rest are user-configurable by means of GE-INTRO software.