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Fault indicators play an important role in the effective operation and maintenance of modern power grids, helping to improve reliability, efficiency, and safety

Short-Circuit and Earth Fault Indicators

A Fault indicator is a device that is used in power grids to quickly detect and locate faults or abnormalities in the electrical system. The device is designed to continuously monitor the power grid and can detect faults such as short circuits, overloads, and earth faults.

When a fault is detected, the smart fault indicator sends a signal to a monitoring center or control room, alerting operators of the problem. It can also provide information about the location and severity of the fault, allowing operators to quickly dispatch maintenance crews to the affected area to repair the fault.


The use of smart fault indicators in power grids has several benefits. Firstly, it helps to improve the reliability and efficiency of the power grid by reducing the time it takes to detect and repair faults. This can help to minimize the impact of outages and reduce downtime for customers.


Additionally, the use of smart fault indicators can also detect SEF faults and help to reduce maintenance costs and improve worker safety by allowing maintenance crews to focus on repairing faults in specific areas, rather than searching for the fault manually.

Overall, smart fault indicators play an important role in the effective operation and maintenance of modern power grids, helping to improve reliability, efficiency, and safety.

Our Smart Short Circuit and Earth Fault Indictors s are capable of not only determining fault indication but also provide real-time critical network data such as.  

  • Monitoring of the parameters voltage (V), current (I), load flow

  • direction (B↓ or A↑), power factor (cos φ), power (P, Q, S), energy (E), temperature (T) and frequency (f)

  • High-precision current and voltage measurement with up to 0.5% accuarcy

  • Limit monitoring: V, I, P, Q, T

  • Earth leakage

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Local Navigator LED and Flag

Overhead Short-Circuit Fault Indicator

The NAVIGATOR short-circuit indicator is an electronic device which is designed for distribution and transmission overhead lines. The indicator is provided with a self-adjusting load-dependent control of the trip current level. This function allows the indicator to continuously sample the load current on overhead lines and electronically set a corresponding trip value for fault detection as a function of the load current. The maximum load current sampled by the indicator, is kept in a memory for a period of at least 72 hours. Thus, the indicator is most favorably adapted to the network to be monitored, even if low load is currently present.

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Smart Navigator FCI (DNP3)

Overhead Directional Short-Circuit Fault Indicator and Conductor Temperature Monitor

The Smart Navigator Overhead fault circuit indicators are designed to operate with all the features found within standard series fault circuit indicators from Horstmann, with the additional benefit of

capturing all available data and feeding this information back to distribution automation

systems to provide further valuable information, with the possibility of local logging if this

information is not required to be fed back into a SCADA system. Reporting of data may

vary between devices, depending on how much and what  information is required. This is

selectable via simple software settings.


The Smart series of overhead and underground devices enable remote or local data monitoring of information such as, but not limited to, maximum demand, load flow, active power, peak demands, directional fault information and conductor temperature Monitor facilitating fault finding, as the faulty section is easily identified locally and by the control room.

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Smart Navigator 2.0 SWER

SWER Overhead Distribution Circuit Fault Indicator

The Smart Navigator 2.0 SWER fault indicator is designed for Single Wire Earth Return (SWER) overhead distribution circuits and/or low current lines (lightly loaded). It quickly and accurately enables crews to determine the status of the system and the location of faults.

The SWER fault indicator devices are mounted directly onto the conductor and can detect fault-currents as low as 6A, levelled automatically with a factor of 1.4 times peak load current. Fault detection, including direction to the fault location, is indicated by bright flashing LEDs. 


The SWER fault indicator can operate on overhead lines with little to no current (from 0A) - it does not rely on the line current for functionality. 

Not only can it be used for local indications (local LED) only, the SWER fault indicator can also be a Smart remote fault indicator, when paired with a Pole Master (pole mounted communications box) to transmit data to SCADA. 

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ComPass B 2.0 Series

Underground Directional Short-Circuit and Directional Earth Fault Indicator

In addition to the short-circuit and earth fault function, ComPass B 2.0 supplies the collected measured values of current, voltage and power from the RMU. The addition of a PT100 sensor can measures the temperature of the transformer or the kiosk substation. All measured values limits can be defined, which can also be transmitted to the SCADA control room. The voltage coupling/measurement is done via the capacitive VDS system or via resistive (ohmic) voltage sensors.

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Control ComPass Bs 2.0

Underground Directional Short-Circuit and Directional Earth Fault Indicator

The Control ComPass Bs 2.0 is suitable for use in substations with a remote control connection of the electrical power distribution in a medium voltage network.


In addition to the functions of the ComPass B 2.0, the Control ComPass Bs 2.0 offers a control function for switching a load-break switch or circuit-breaker. A free assignment of 6 binary inputs in combination with a freely programmable logic (PLC functionality) enables the user to define the switching conditions in a flexible manner. Random information, such as the SF6 gas disruption or HV tripped fuse, can be captured via the binary inputs.

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Sigma D Series

Underground Directional Short-Circuit and Directional Earth Fault Indicator

The SIGMA D Series is a combined directional short-circuit and directional earth fault indicator for medium-distribution networks. The device is current transformer powered, thus no auxiliary supply is required.

The SIGMA D+ provides additional earth fault detection methods for resonant-earthed and isolated networks.

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Sigma F+E 3 Series

Underground Short-Circuit and Directional Earth Fault Indicator

The Sigma F+E 3 2.0 device is a combined short-circuit and earth fault indicator. It is designed to detect, display and remotely indicate short-circuit and earth faults in medium voltage distribution networks.

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OPTO-F+E Series

Underground Short-Circuit and Directional Earth Fault Indicator

The OPTO-F+E Series is a combined short-circuit and earth fault indicator. Due to its measuring principle, the earth fault indication is only suitable for networks with low-impedance or solidly earthed neutral as well as for operation in radial or open ring networks. Fibre optic cables for electrical isolation between indicator and current transformers make it a easy retrofit solution.

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