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DGBV-EP
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| DIGITAL GENERATOR AND GENERATOR-TRANSFORMER
UNIT PROTECTION |
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| The digital generator and generator-transformer
unit protection of type DGBV-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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| DGBV-EP digital generator and generator-transformer
unit protection is a complex system, consisting several cooperating microprocessor-based
units of the EuroProt product family. The complex system is always individually
compiled by our experts, based of planning and designing experiences of
several decades, fulfilling the individual and special requests according
to the ordering.
The main considerations of developing the DGBV-EP digital generator and
generator-transformer
unit protection are:
- covering all protection and automation tasks in connection with the
objets to be protected
- optimal assignment of protection function to the measuring transformers
- providing the necessary back-up protection functions
- fulfilling the individual and special requests of the user
- cost-optimised solution
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| Main features |
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Configuration of the complex protection:
- independent racks in cabinet or cabinets, powered by independent power
supply units
- individual EuroProt protection units in each racks, with dedicated
connections to measuring transformers, optimal functional assignment
- fully numeric signal processing in each functions
- the individual functional units send commands and signals to the trip
matrix located in independent unit, where, according to the setting,
each signal of protection functions is directed to the appropriate interfering
unit. The individual interactions can be disabled or enabled here, as
needed in the commissioning procedure
- signals and information can be received from auxiliary protective
devices (gas protection, temperature protection)
- continuous monitoring of CB circuits
- individual communication with each units in racks, LED signalling,
display of numeric values and text messages
- the individual racks are connected to fibre-optic loops, polled by
PROTECT monitoring and relay setting program
- digital event recorder, for monitoring the starting and trip commands
of individual protection functions with 1 ms time resolution and for
recording the measured analogous signals
The usual protection and automation functions are:
- differential protection for the generator, for the transformer, for
the auxiliary transformer and for the whole unit
- overcurrent protection
- field failure protection
- under-impedance protections
- definite time overload and overcurrent protection
- unbalanced load (negative phase sequence) protection
- overvoltage protection
- reverse power protection
- stator earth fault protection
- rotor earth fault protection
- multi-stage underlover frequency protection
- automatic synchroniser, which can be disabled automatically in case
of protection operation
Hardware characteristics of individual devices:
- fully numerical type, with individual A/D converters, digital signal
processors (DSP) and separate main processor
- opto-coupler inputs
- output contacts
- type of output contacts (NC, NO) can be selected at design time
- design for 19" rack cabinets
Communication:
- relay setting with 2x16 character LCD display, suitable also for text
messages and for event log display
- on-line screen of auxiliary PC for support of commissioning
- auxiliary communication connection selectable for RS 232 or fibre
optic cable
- optional SCADA connection with IEC 870 protocol
- parameters can be saved and saved parameters can be downloaded again
- real-time clock with battery-fed RAM, (which can be synchronised via
fibre-optic connection by auxiliary PC, by the SCADA system, or via
opto-coupler digital input)
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| Working principles |
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The EuroProt devices are microprocessor-based
systems, the functions and their variations are realised by software. The
devices contain several 87C 196 type 16 bit micro-controller and DSP signal
processor. The software is stored in EPROM, the text messages to be displayed
are stored in EPROM too. The parameter settings are stored in EEPROM. The
events are recorded in battery-fed RAM. The man-machine communication is
performed by a six button-keypad on the front plate, the 2x 16 character
LCD display above them, with seven signal LED-s and with two SW pushbuttons.
With external PC and with the handling software the device can be set, checked
and monitored more easily. To display the rows and columns of the trip matrix
and for other important signalling a large LCD display is provided, containing
further LED-s.
The analog current ad voltage inputs are connected to the multiplexer and
further to the A/D converter via intermediate measuring transformers, where
the sampling time is 0,5 ms for each current and voltage signal. The sampled
digital values of the 16 bit A/D converter are transported to the CPU via
high-speed serial bus by the CAN controller. The digital signal processor
performs arithmetic operation with high speed. The output of the DSP is
the evaluated result of the measurements, these signals are connected as
"relay started" signals to the central processor. The central
processor performs logic function and time delay measurements. The opto-coupler
inputs and relay outputs communicate with the central processor via parallel
bus.
The detailed information of the individual protection functions are described
in different information sheets. |
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| Basic technical data of individual devices |
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Rated secondary current, In
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1 A or 5 A |
| Rated secondary voltage (line-to-line),
Un |
100 V or 200 V |
| Rated frequency |
50 Hz or 60 Hz |
Overload capacity, voltage circuit, thermal, continuous
current circuit, thermal, continuous
1 s |
2xUn/Ö3
4xIn
100xIn (In=1 A), 50xIn (In=5 A) |
| Dynamic current limit |
100xIn |
Accuracy of digital impedance protection
functions (above 50% In)
Accuracy of digital current protection functions (above 50% In)
Accuracy of timers
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± 5%
± 2%
± 3 ms (steps 10 ms)
± 12 ms (steps 1 s) |
| Resetting ratio of current relays |
95% |
| Output relay contacts |
as requested |
| Type of output contacts (NO/NC) |
as requested |
Output contacts, electrical data:
rated switching voltage
continuous load current
making current
DC breaking capability at 220 V,
at pure conductive load
at load ofLIR = 40 ms
Optionally, at load of L/R = 40 ms |
250 V
8 A
16 A
0,25 A
0,14 A
4 A |
Auxiliary DC voltage (the same supply unit)
voltage tolerance
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220 V or 110 V
88 V to 310 V |
| Permissible 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 |
| Electrostatic 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 DGBV -EP complex protection equipment is
delivered in a steel-sheet cabinet with standard 19" hinged rack system
and locked door, accessible from the front side. When selecting the cabinet
type the manufacturer can consider the special requirements of the user.
If not specified at ordering, the cabinet is of RITTAL PS type. |
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| Options |
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- digital disturbance recorder (see separate information sheet)
- SCADA connection (see EuroProt system information sheet)
- relay contacts with 4 A breaking capability
- output circuit supervision in each phase
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| Ordering data |
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| When ordering, our experts are ready for consultation and
for the necessary engineering activity. |
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