Thytronic SVF5940
Interface protection relay with voltage, frequency and rate of change of frequency protection to ENEL DK5940.
The Thytronic SVF5940 is an interface protection relay that disconnects generators running in parallel with the low voltage network on abnormal voltage or frequency, to ENEL DK5940 and CEI 11-20. This Modbus RTU template reads the phase voltages, frequency, rate of change of frequency, trip flags and thresholds, and lets you send store, reset and test commands from ModbusCloud.
- Protocol
- Modbus RTU
- Connection
- RS485, 9600 baud
- Registers
- 51, read and write
- Brand
- Thytronic
- Key readings
- Phase voltages · Frequency · Rate of change of frequency · Trip flags · Breaker input · Protection thresholds · Self-test status
- Available commands
- Rated frequency · Voltage input mode · Breaker failure time · Store and reset commands · Protection test
- Compatible models
- SVF5940
- Last updated
Registers (51)
47 read, 15 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Voltage L1 | V | Read | |||
| Voltage L2 | V | Read | |||
| Voltage L3 | V | Read | |||
| Frequency | Hz | Read | |||
| Rate of Change of Frequency | Read | ||||
| Protection Trip Flags | Read | ||||
| Breaker Input DIGIN1 | Read | ||||
| Self-Test Level | Read | ||||
| U< Pickup (x Un) | Read | ||||
| U<< Pickup (x Un) | Read | ||||
| U> Pickup (x Un) | Read | ||||
| U>> Pickup (x Un) | Read | ||||
| f< Pickup (x fn) | Read | ||||
| f<< Pickup (x fn) | Read | ||||
| f> Pickup (x fn) | Read | ||||
| f>> Pickup (x fn) | Read | ||||
| df/dt Pickup (Hz/s) | Read | ||||
| Frequency Inhibit Voltage (x Un) | Read | ||||
| Breaker Failure Time | s | Read and write | |||
| Breaker Contact Type | Read and write | ||||
| Rated Frequency | Hz | Read and write | |||
| Measurement Reading Mode | Read and write | ||||
| Voltage Input Mode | Read and write | ||||
| Keypad Setting Access | Read and write | ||||
| Rated Voltage Un | V | Read | |||
| Relay K1 Functions | Read | ||||
| Relay K1 Timer tTR1 | ms | Read and write | |||
| Relay K2 Functions | Read | ||||
| Relay K2 Timer tTR2 | ms | Read and write | |||
| Relay K3 Functions | Read | ||||
| Relay K3 Timer tTR3 | ms | Read and write | |||
| Relay K4 Functions | Read | ||||
| Relay K4 Timer tTR4 | ms | Read and write | |||
| Settings Command | Write | ||||
| Reset Command | Write | ||||
| Test Command | Write | ||||
| Recorded Data Default Command | Write | ||||
| Modbus Address | Read and write | ||||
| RS485 Baud Rate | Read | ||||
| Enable TX Delay | ms | Read | |||
| Start Count U< | Read | ||||
| Trip Count U< | Read | ||||
| Events Stored | Read | ||||
| Event 1 Reading Mode | Read | ||||
| Event 2 Reading Mode | Read | ||||
| Event 3 Reading Mode | Read | ||||
| Event 4 Reading Mode | Read | ||||
| Clock Year | Read | ||||
| Set Clock Year | Read | ||||
| Device Identification | Read | ||||
| Mean Cycle Time | Read |
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Show the phase voltages and the frequency of the grid connection on a dashboard and keep a year of history per value.
- Send an e-mail or webhook alert as soon as the trip flags rise above zero.
- Watch the rate of change of frequency to see how close the grid gets to the trip thresholds.
- Check the voltage and frequency thresholds remotely before an inspection of the interface protection.
- Watch the self-test status to spot relay or breaker failures early.
Installation
Wire the rear RS485 terminals A and B of the SVF5940 to the RS485 port of the ModbusCloud Gateway, and terminate the bus at both ends with 120 Ω.
On the relay, check the Modbus address, baud rate, parity and stop bits with the keypad or ThySetter (default 1, 9600 baud, no parity, 1 stop bit).
In ModbusCloud, add a Modbus device on the RS485 port of the Gateway with the same address, 9600 baud, 8 data bits, no parity and 1 stop bit.
Import the Thytronic SVF5940 template and check that the voltages and the frequency come in and that Device Identification shows 19.
Compare the voltages with the relay display or ThySetter, and set the VT primary voltage on the relay if you read primary volts.
Things to watch for
The Gateway gets no answer from the SVF5940. What should I check?
Check that the address, baud rate, parity and stop bits on the relay match the device in ModbusCloud, and that A and B are not swapped. Terminate the bus with 120 Ω at both ends. The front RS232 port is only for a PC with ThySetter.
The voltages do not match the relay display. Why?
With the default Reading Direct the relay reports primary volts, calculated from the VT primary voltage set under Set, Base. With Reading Relative it reports multiples of Un. Check the reading mode and the rated values on the relay and compare again.
I changed a setting, but it is gone after a restart. Why?
The SVF5940 keeps changed settings in temporary memory until it receives the store command. Write Store to the Settings Command register, or Clear to discard the changes, and read a setting first before you write it. The thresholds and their delays are written as one message, so change those with the keypad or ThySetter.
Some values stay empty while the voltages come in. Is that normal?
The clock, the identification, the event records, the counters, the thresholds and the output relay functions are part of larger messages that the relay may only send as a whole. When one of those stays empty, the voltages, frequency and trip flags are still read as normal.
Can a command from ModbusCloud disconnect the generator?
Yes. A test with trip operates the output relays and opens the interface breaker, so the generator disconnects. Only use these commands during commissioning or maintenance, with the plant in a safe state.
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