Sigma DM
Fault direction indicator with Modbus RTU
The Sigma DM is a directional short-circuit and earth fault indicator with clear fault direction indication. Equipped with an RS485 interface for transmitting measured values and error messages via the Modbus RTU protocol. Suitable, closed current sensors are available for every gas- and solid-insulated medium-voltage system for installation via the cone in the cable panels. It is also possible to retrofit divisible current sensors around the medium-voltage cable, even in air-insulated systems. The phase voltage and the reference signal for fault direction indication are provided by the WEGA voltage test system. The voltage signal is automatically adjusted to the switchgear over 24 hours or can be adjusted manually using buttons or the Sigma Explorer configuration software.
Operational readiness is indicated by the status LED.
The Sigma DM provides 6 earth fault location methods for all neutral point treatments such as RESPE; NOSPE; KNOSPE or OSPE (isolated), which can also be used in combination. Active earth fault location methods such as pulse location are supported. Two digital inputs are freely configurable and can detect status messages such as switch states in addition to the test/reset function. With the exception of the earth fault wiper method, no auxiliary voltage is required for fault location if the operating current >is 5 A.
Product features
- Transformer-powered short-circuit direction indicator and earth fault direction indicator for all networks and neutral point treatments
- Remote signaling via RS485 with Modbus RTU
- Requires only three phase current sensors for all earth fault location methods
- Earth fault detection with up to six different earth fault detection methods, can also be combined
- Independent, fully automatic voltage calibration
- Simple and flexible parameterization via DIP switch or USB
- Event memory for error evaluation
- LED status display, multicolor
- Sigma Explorer software: Commissioning, parameterization and reading out the event memory via the front USB port
- With wide-range power supply 24 V to 230 V AC/DC
Phase-selective short-circuit and earth fault display
Clear error direction display
Differentiation between short-circuit and earth fault
Status indicator LED
Your added value
- Immediate error direction detection
- Availability of measured values and error messages in the control room via RS485/Modbus RTU and on site via USB with Sigma Explorer software
- Fast commissioning and parameterization
Reverse polarity protected plug-in terminals for quick and easy installation
Connection for voltage coupling (Wega)
Auxiliary voltage connection
Earthing connection
Technical data
| Sigma DM | |
|---|---|
| Short-circuit indicator | ✅ |
| Earth fault indicator | ✅ |
| Earth fault location method | Continuous earth fault, earth short circuit, cos φ and sin φ methods, pulse detection, earth fault wiper |
| Measured values |
|
| I>> Response valuesShort-circuit current | DIP: 400, 800, 1,000, 2,000 A, self-adjustmentSW: 10 – 2,000 A |
| tI>> Response delay | 50 – 2.000 A |
| IE> Response valuesEarth fault current | 10 – 1.000 A |
| tIE> Response delay | 40 ms – 60 s DIP: On/Off |
| IEP> Response values active residual current cos φ /IEQ> Response values reactive current sin φ | 1 – 200 AtIEP> / tIQP> Response delay: 40 ms – 60 s |
| UNE> Response values continuous earth fault | 0 – 100 %tUNE> Response delay: 40 ms – 60 s |
| U> Response valuesOvervoltage | 100 % – 200 % |
| U< Response valuesUndervoltage | 0 % – 100 % |
| ΔIE> Response valuesPulse localization (clock stroke) | 1 – 100 A |
| Measuring accuracy phase currents | 3 % (0 – 630 A, resolution 1 A)5 % (630 – 1,500 A)10 % (1,500 – 2,000 A) |
| Display |
|
| Remote signaling / communication | RS485 / Modbus interface |
| Reset |
|
| Supply | |
| External auxiliary voltage | 24 – 230 V AC/DC |
| Internal power supply | Long-life lithium cell>1,000 h Total flashing time of the LED>1,000 display activations |
| Housing | Polycarbonate, IP40 |
| Temperature range | -30 °C to +70 °C |
All important documents for the device
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