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DFR-EP
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| DIGITAL FREQUENCY RELAY |
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| The digital frequency relay of type DFR-EP
is part of device family named EuroProt.This short description contains
special data of this type. General and common features of EuroProt family
can be found in the EuroProt system information sheet. Accordingly it is
proposed to study both this short description and system information sheet
too, in order to understand the device entirely. |
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| Application field
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| The digital frequency relay of type DFR-EP
is applied on large power system to avoid dangerous system frequency drop
and consequently system breakdown when power plant generators drop out.
The frequency relays switch off predetermined consumers. In some case, the
frequency relay is used to generators as a frequency rising relay for overspeed
protection. |
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| Main features |
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- Four independent frequency stages or three frequency stages and one
rate-of-change frequency stage (df/dt) combined with underfrequency
detection
- Underfrequency or overfrequency relay for first three stages, underfrequency
for forth only
- Separate blocking feature for any stages
- Very high frequency accuracy (± 0.005 Hz)
- Large frequency and time delaying range to be set
- Settable release margin (hysteresis)
- Operation blocking on voltage break-down
- Three voltage inputs with priority circuit
- Consumer-friend modern digital parametering (setting) method
- Fast checking possibility of the protection setting data
- Password protection against unauthorized setting action
- Fast inquiring possibility of actual requency data and sum of protection
working counters
- 8 output contacts, programmable by softwre matrix
- Real time clock handling synchronizable by external PC or by local
area radio transmitter
- RS 232 or optical fibre cable for external communication
- Immediately appearing "messages" on occurring protection
events
- Event recorder with 50 protection events with real date and time
- Deleting all events by hand may be made by external PC only
- Each frequency stage listed above may be separately blocked and made
active
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| Working principle |
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Voltage sample frequency is 1 kHz. The frequency
relay determines the frequency value as an average of four cycles by an
algorithm calculating the measuring value in each cycle. Each of the three
first stages can be under or overfrequency relay depending on setting value
of limiting frequency. If it is set higher than its setting frequency value,
the stage is underfrequency relay, and if it is set lower, the stage is
an overfrequency relay.
The forth stage may be set to underfrequency stage only (if the rate-of-change
frequency relay is set to zero), or to underfrequency and rate-of-change
frequency relay.
The releasing margin (hysteresis) has to be set to avoid the unpleasant
effect of frequency fluctuation and the detection of actual operation frequency.
All the four stages has an independent timer.
Setting (parametering) and checking of protection, inquiring of the working
data, events and signals, setting of software matrix, and handling of automatic
signals (messages) is possible with a built-in LCD of 2x16 characters and
six push-buttons on interactive mode by the aid of a menu system or with
an external PC. A handling program is delivered together with the DFR-EP
digital frequency relay to make handling functions possible by an external
PC. |
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| Technical data |
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| Rated secondary voltage, Un |
100 V, 200 V or other |
| Voltage range to accurate frequency measurement |
(0,4-1,3)xUn |
| Overload capacity, termal, continuous |
1,3xUn |
| Rated frequency |
50 Hz |
| Setting ranges |
| Voltage relay |
40-90 V |
| Frequency relay |
45-55 Hz, step 0,01 Hz |
| Hysteresis |
0,02-0,2 Hz |
| Limiting frequency |
45-55 Hz, step 0,01 Hz |
| Rate of change frequency relay (df/dt) |
0-10 Hz/s, step 0,1 Hz/s |
Each frequency relay, pick-up timer
reset timer
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0-50 s, step 0,05 s
0-1,5 s, step 0,15 s |
| Self-check monitoring system, signal timer |
0,1-10 s, step 0,02 s |
| Blocking a frequency stage |
setting to limiting frequency |
Accuracy, frequency relay
rate of change frequency relay (df/dt)
timers
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± 0,005%
± 0,05 Hz/s
± 2 ms |
| Principle operating time without time delay |
80 ms |
| External communication type |
RS 232/fibre optical cable |
| External communication speed (BaudRate) |
150 do 19200 |
| Daily automatic self-check time |
0 to 23 h 59 min |
| Automatic self-check, block |
to 60 min |
| No. of substations in a system |
0-253 |
| No. of devices in substation |
0-253 |
| Output relay number |
8 pcs |
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Output contacts ratings:
rated switching voltage
continuous load current
switching on current
breaking current at 220 V DC
pure conductive circuit 0,25 A
L/R = 40 ms load
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250 V
8 A
16 A
0,25 A
0,14 A |
Auxiliary DC voltage (the same supply unit)
voltage tolerance
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220 V or 110 V
88 V to 310 V |
| Permissive ambient temperature |
0o to 50o C |
| Insulation test (IEC 255) |
2 kV, 50 Hz
5 kV, 1.2/50 µs |
| Disturbance test (IEC 255) |
2.5 kV, 1 MHz |
| Electrostic discharge (ESD; IEC 801-2) |
8 kV |
| Burst test, (IEC 801-4) |
2 kV |
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| Design, size |
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The DFR-EP digital frequency relay is a member
of the device family EuroProt. It has two different designs. The one is
a device for rack mounting to a 19" standard cabinet frame, the other
is a flash mounting or raising mounting device to a panel. Its size depends,
of course, on the design chosen. The protection is controlled by microprocessors
and equipped with module system of plugged in PCB's, set up of IC's.
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Design
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Width
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Height
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Depth
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Rack mounting
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483 mm
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132,5 mm
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201 mm
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Panel mounting
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277 mm
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250 mm
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250 mm
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Weight 8 kg. |
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| Information required with order |
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- Type of relay [DFR-EP]
- Auxiliary dc battery voltage [220 V, 1.10 V, or other]
- Rated V.T. secondary voltage [100 V, 200 V]
- Cases
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