DTI2-WP
 
DIGITAL OVERCURRENT PROTECTION
 
The type DTI2-WP device belongs to the WProt device family. Features of this device family are nearby so varied as the other up-to-date devices made by ELKO-PROTECTA but these are extremely small-sized and their mounting is very simple. The devices are stackable to a standard W-rail, which is generally used by the electrical power industry. The small-sized design is produced by a healthy relational compromise so that wide ranging application is not limited.
 
DTI2-OP
 
Main features of WProt family
 
  • it is a small-sized device based on microprocessor and stackable to a standard W-rail
  • it is smaller as an other device of similar feature
  • it has three analogue inputs (for receiving currents, voltages)
  • four independent output relay contacts which can be freely programmed by a software matrix and each has possibility to be set for sealing-in
  • two optical fibre connectors (transmitter, receiver) for communicating with a SCADA system or with a PC, and for programming the protection, receiving on-line informations, and reading events stored
  • eight signal LED on the front plate of protection for getting additional informations about the operation
  • acknowledge pushbutton for acknowledgement of signals and for solving relays being sealed-in
  • terminals are on the front plate of case
Application field
 
The digital complex overcurrent protection of type DTI2-WP with independent or dependent time delaying is used in generating, transmitting and distributing establishments as well as at consumers of an electric power system on such fields where short circuits, faults or abnormal operations cause overcurrent exceeding the rated current, hence the events caused overcurrent can selectively be catched by overcurrent relays. Typical application field is a protection for short circuit, back up protection and protection agains overloading. The WProt devices have a narrow place requirement so they are practically used where it has essencial benefit, e.g. enlargement, small built in place.
 
Main features
 
  • .the overcurrent protection is designed by phase (3x [I>,I>>];2x[I>,I>>])
  • three or two phase type may be required (3f, 2f)
  • the two phase type may be also required with 3Io>, 3Io>> zero sequence overcurrent relais (2f Io)
  • if only earth fault protection is required, the 3Io> relay may be completed with zero sequence directional detection as well (Io j)
  • the overcurent relais may be separately set to independent or dependent characteristic
  • the dependent characteristic may be set to nomal inverse very inverse, extremly inverse and long time earth fault inverse characteristic
  • by the help of a software matrix, each overcurrent relais starting and the two additional timers can make operating of the output relais, starting their timers and the two additional timers
  • the overcurrent relais may be set in per cent of the main C .T .rated value, which should be set
  • operation field (greatest and smallest angle values) as well as hysteresis angle range (resetting ratio) of the zero sequence angle relay may be set
  • the protection is provided with automatic and manually started self monitoring system
  • eight LED gives informations about working and it has four output relais, any of which may be programmed to self-sealing
  • it can be programmed (set) through an optical fibre cable only
  • its handling may be carried out by an external PC (e.g. by a laptop) or by a central computer (e.g.SCADA)
Based on those written above, four types may be ordered as follows:
  • DTI2-WP-3f
  • DTI2-WP-2f
  • DTI2-WP-2f I0
  • DTI2-WP-I0 j
Setting (parametring) and checking of protection, reading of the working data, events and signals, setting of software matrix, and handling of automatic signals (messages) is possible with external PC or other external computer. A handling program is delivered together with the DTI2-WP protection to make handling functions possible. The device has to handle on interactive mode by the aid of a menu system.
 
Technical data
 
Rated secondary current, In
Rated secondary zero sequence current, In o
(other value can be given when ordering)		 1 A or 5 A
0.1 A, 1 A or 5 A
Main C.T., primary current, settable 50 to 1500 A, steps 25 A
Zero sequence main C.T.,
primary current, settable
toroidal type C.T., ratio
50 to 1500 A, steps 25 A
150/5 A
Overload capacity, continuous
1 s 		2xIn
100xIn (if In = 1A)
50xIn (if In = 5 A)
Dinamic current limit 100xIn
Accuracy, overcurrent relais (over 50 %) ± 2 %
Digital timers, (at step of 10 ms)
(at step of 1 s)		 ± 3 ms
± 12 ms
Resetting ratio, overcurrent relais (on request, other value) 95%

Overcurrent relais, setting range in percent of main C.T. primary current
high and low setting overcurrent relais
zero sequence relais
in case of toroidal type C.T.

range
50 to 2500 %
10 to 104 %
10 to 104 ‰		 steps
5%

5‰
Timers, setting range 0 to 60000 ms 10 ms
Dependent characteristic constant k= 0.02 to 1 0.02
External communication RS 232/optical fibre cable
External communication, transfer speed (BaudRate) 150 to 19200, steps 2 times
Daily automatic self check, starting time 0 to 23 hour 59 minute, steps 1 min
Automatic self check, blocking setting to 60 minute
Output relais number (programmable by software matrix)
 4 pcs print relais
Output contacts, electrical data:
rated switching voltage
continuous load current
making current
Breaking capability at 220 V DC,
pure conductive load
load of L/R = 40 ms
250 V
8 A
16 A

0.25 A
0.14 A
Auxiliary dc voltage (the same supply unit)
voltage tolerance		 220 V or 110 V
88 V to 310 V
Permissive ambient temperature 0°C to 50°C
Insulation test (IEC 255) 2 kV, 50 Hz
5 kV, 1.2/50 ms
Disturbance test (IEC 255) 2.5 kV, 1 MHz
Electrostatic discharge test (ESD; IEC 801-2) 8 kV
Burst test, (IEC 801-4) 2 kV
 
Design, size
 
The DTI2-WP overcurrent protection is built into the closed dustproof steel case, controlled by microprocessors, set up with IC's, placed to PCB's. The case may be stackable to a standard W-rail, width in the rail is 120 mm. 16 terminals are placed on the front plate of case, through them external connection may be made. The optical fibre cable connections are put to the upper part of the front plate at left.

Width
Height
Depth
120 mm
90 mm
90 mm
 
Data to be ordered
 
  • Type of protection [ e.g. DTI2-WP-2f Io)
  • Rated C.T. current [1 A, 5 A]
  • Feeding of zero sequence relais [main C.T., toroidal type C. T.]
  • In case of toroidal type C.T., its ratio [150/5 A or others]
  • Whether is the logical (d.c.) busbar protection contact an NC or NO type?
  • If an output contact is needed for alarm of the monitoring system an NC contact of K4 should be ordered