Electric power distribution carries electricity from the transmission system to individual consumers, thus marking the
final stage in the delivery of electric power. With the use of transformers distribution substations connect to the
transmission system and lower the transmission voltage to medium voltage (2 kV – 35 kV). To protect this important
link, we offer the distribution network fast and accurate protection, including a wide range of specialised protection
functionality, e.g. for feeders, transformers and busbars.

Reliable intermittent earth fault detection
Intermittent earth faults are a growing problem for compensated distribution networks with large amounts of underground cabling. Arcteq Feeder protection IEDs come equipped with a proven and patented algorithm that –
combined with the high accuracy of the relay – detects and isolates intermittent earth faults more reliably than any
other relay brand on the market.

Superior fault analysis
Data acquisition and fault analysis are becoming increasingly important. Arcteq feeder protection IEDs, equipped with
0.2s measurement accuracy, make additional measurement devices on the substation obsolete. The high resolution of 64 samples / cycles enables a superior fault analysing capacity with the analysis of transients up to the 31th order.

Ultra-fast arc protection
Arc protection at distribution substations is often considered an important life insurance for the operating personnel.
The Arcteq ultra-fast arc protection is especially designed to detect and isolate arc faults with the best possible
accuracy and speed.

Featured products for DSO
Feeder Protection IED AQ-F215
Feeder Protection IED AQ-F255
AQ 100 Arc Protection System
Transformer Protection IED AQ-T257


In a wholesale electricity market, the System Operator manages power system security in real time and co-ordinates the supply of and demand for electricity, while avoiding frequency fluctuations or supply interruptions. Transmission line operations require reliable, accurate and fast operation of the protection IED. Today accurate measurements are especially important for grid operators.

Full protection and control
The Arcteq AQ 200 series is designed for extreme accuracy with up to class 0.2S power and energy measurement as well as fast operation. The sampling frequency of 3.2 kHz and a 5 ms internal update cycle ensure that we, according to customer requirements, can provide full protection and control to any transmission line and substation up to 1000kV. Moreover, native IEC 61850 and several other open communication protocols ensure communication and data transfer to e.g. SCADA systems and protection devices from other manufacturers. Arcteq provides variety of choices for line protection, busbar protection, multi-winding transformer protection and bay control. 

Featured products for TSO
Bay control IED AQ-S255
Busbar protection IED AQ-B398
Line protection IED AQ-L359

Utility project references