TR-7576 Transformer Protection Relay with 6 Channel Temperature Scanner

The TR-7576 is designed for safe operation of medium voltage cast resin/dry type transformers. It is suitable for control room as well as marshalling box installation and is built for long and trouble-free operation under extreme conditions of services associated with transformer.

Three numbers of user settable set-points can be used to control cooling fan, to warn the user of high temperature and to shut down the transformer in case of excessive heating.

Six nos. of Pt-100 RTD sensors allow the user to monitor the temperature of six windings located inside the transformer.

TR-7576 is programmed to note and store maximum temperature of the winding. Facility extends to recall this information and to clear it for fresh recording.

TR-7576 comes in multiple variants featuring different output options based on the model number.

TR-7576 has one analog output signal (4-20 mA). This can be configured to represent the temperature of any of the six channels or the temperature of the hottest channel.

TR-7576-C comes facility for computer communication using RS-485 with MODBUS TRU slave protocol.

Technical Specifications:

• Inputs: 6 nos. of RTD sensors (Pt-100, IEC-60751)
• No. of Set-points: Three (Alarm, Trip & Fan On)
• Temperature indication range: -20 to 250 °C
• Set point range: 20 to 220 °C
• Accuracy: +/- 1 °C
• Dead Band (relay differential): Fan & Trip: 8 °C, Alarm: 5 °C, (Factory set)
• Display Speed: 4 seconds (Factory set)
• Display: 3 Seven Segment 1/2" displays for displaying temperature
• 1 Seven Segment 1/2" display for displaying channel number

Mechanical:

• Overall Dimensions: 215 (H) x 265 (W) x 130 (D) mm
• Mounting: Wall mounting by 3 nos. M6 screws
• Weight: 3.5 kg approx. (unpacked)
• Enclosure: M.S. Sheet Box, powder coated, with acrylic viewing window (IP-52)

Electrical

• Supply Voltage: 90 - 270 VAC/DC (Optionally 20 - 50 VAC/DC)
• Outputs: Four relay contacts (one C/O contact for - Fault, Fan, Alarm & Trip)
• Communication (depending on variant):
• TR-7576: One analog (4 - 20 mA) output (corresponding to 0 to 200 °C max. load 300 ohms, linearity 0.5% w.r.t. local indication
• TR-7576-C: RS485 communication (1KVDC isolated) with MODBUS RTU slave protocol
• Contact rating: For resistive load, 5A @ 230VAC & 0.5A @ 125VDC
• For inductive load, 5A @ 230VAC (cosθ = 0.4) & 0.3A @ 125VDC (L/R=7msec)

Relay operations:

• Fault: Will energise after few seconds of power-on and de-energise on detecting fault condition. Fault relay will remain ON in normal conditions.
• Fan: Will energise if any channel's temperature exceeds Fan set point.
• High: Will energise if any channel's temperature exceeds High set point
• V. High : Will energise if any channel's temperature exceeds V. High set point
• Terminals: Combicon screw caged, suitable for 2.5 mm² solid conductors.

• Insulation: Insulation resistance shall be 100 Mohm or more when 500 VDC is applied between each terminal shorted together and earth. Controller will withstand 2KV rms at 50/60 Hz. for 1 min, applied between all relays & supply terminals shorted together & earth.
• Power consumption: Max. 15VA

Environmental

• Operating conditions:
• Ambient temperature: -20 °C to 70 °C, Relative Humidity : 95% Max non-condensing
• Storage Temperature: -20 °C to 85 °C
• Test conditions: Ambient temperature: 27 °C +/- 5 °C, Relative Humidity: 20 - 80% non-condensing
• Vibration: 10-150 Hz, 0.0004" displacement