Surge Protection

Ensto’s surge arrester range includes efficient solutions and products for overvoltage protection of distribution and transmission networks, AC and DC railway systems, and cable sheaths. The overvoltage is usually caused by lightning and switching actions, and proper protection substantially contributes to the improvement of quality, reliability and availability of power supply networks.
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Optimized size for Distribution Surge Arresters

Ensto has launched a new sub range of VARISIL™ HE Distribution surge arresters. These products are used for limiting transient over voltages in distribution networks, and they offer effective and reliable surge protection for expensive equipment.
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Improving Surge Protection

Surge arresters play a vital role in protecting electrical systems in both distribution and transmission networks. These devices are designed to safeguard equipment from transient overvoltages, often caused by lightning strikes, switching operations, or faults in the network. When an overvoltage occurs, surge arresters quickly redirect the excess energy to the ground, preventing damage to sensitive components such as transformers, circuit breakers, and insulators. In transmission networks, surge arresters are typically installed at substations or along overhead lines, while in distribution systems, they are placed near transformers or at key network junctions to enhance system reliability and minimize downtime.

This protection ensures the continuous operation of the electrical system, reducing the risk of equipment failure and service interruptions. By minimizing damage, surge arresters also help reduce maintenance costs, extending the lifespan of electrical assets. Their reliable performance contributes to a stable and cost-effective power supply, making them a key element in maintaining the integrity and efficiency of both transmission and distribution networks.

With more than 75 years of experience in overvoltage protection, Ensto offers products and solutions that substantially contribute to higher quality, reliability and availability of power supply networks. Indeed, more than 5 million VARISIL™ surge arresters are now in service worldwide to ensure an efficient protection.

Designed and manufactured surge arresters to the highest standards and its, wide range of products, ensures years of maintenance-free service in the following segments:

  • Distribution network
  • Substation or Transformer
  • Railway
  • Cable sheath

Ensto' surge arresters are essential for:

  • Protecting electrical equipment
  • Ensuring service continuity
  • Reducing maintenance costs 

Solutions Dedicated to Various Applications

Solutions Dedicated to Distribution Network

Distribution surge arrester

VARISIL HE & HE-S surge arresters are high-performance protective products designed for use in distribution networks. It effectively protects electrical equipment from transient overvoltages caused by lightning or switching events. With its advanced technology, VARISIL HE & HE-S ensures enhanced reliability, safety, and cost-efficiency in power systems.

+ VARISILTM HE 

These surge arresters are dedicated to overvoltage protection up to 36 kV.

+ VARISILTM HE-S

These surge arresters are dedicated to overvoltage protection up to 52 kV.

Both can be supplied with electronic fault indicator or ground lead disconnector.

They are certified as:

  • Distribution Heavy (DH) according to IEC 60099-4
  • Distribution Heavy Duty (HD) according to IEEE C62.11

They are polymer housed gapless surge arresters and the metal oxide resistors are wrapped by a fiber-glass reinforced epoxy resin and housed by a silicone rubber. 

Current design allows the VARISIL™ HE-S to provide double cantilever strength.

Main benefits are: 

  • High resistance to climatic stresses
  • Optimized electrical performance
  • Low Residual Voltage 

Solutions Dedicated to Substations and/or Transformers

VARISIL HI and HTS surge arresters are designed for substations and power transformers. Those robust products safeguard electrical equipment from transient overvoltages caused by lightning or switching events. With advanced materials and technology, VARISIL HI and HTS arresters offer superior reliability, efficiency, and long-term performance.

+ VARISIL TM HI 

These surge arresters are dedicated substations and/or power transformers for networks up to 170 kV and certified as Station Low (SL) according to IEC 60099-4.

+ VARISIL TM HTS

These surge arresters are dedicated substations and/or power transformers for networks up to 245 kV and certified as Station Medium (SM) according to IEC 60099-4

Both are polymer-housed metal oxide surge arresters.

Main benefits are: 

  • Safe overvoltage protection
  • High electrical performance
  • Low weight
  • Maintenance-free 

Solutions Dedicated to Railway

Wide range of surge arresters dedicated to trams and railways installations and used by railways utilities, railways OEM’s and car builders. Their robust design ensures long-lasting performance and cost-effective operation.

+ VARISILTM HDC

VARISIL™ HDC is a polymer housed metal oxide surge arresters for overvoltage protection of equipment on substations, overhead contact lines or vehicles energized by direct current.

+ 8506 & VARISILTM HDP

8506 & VARISIL™ HDP are surge arresters dedicated to railway equipment connected to 1500 V d.c. or 3000 V.d.c. systems. These products are designed to be on top of locomotive's roof.

+ VARISILTM HDT

VARISIL™ HD/T is range of a polymer housed gapless surge arresters for overvoltage protection of rolling stock energized by alternating current.

+ Voltage Limiter type CLS

Voltage limiters type CLS is a range of voltage limiters dedicated to protection of people against hazardous potential rises on unearthed structures. CLS is intended for either a.c. or d.c. systems operated by railway companies. The device is based on the specific electrical properties and arc resistance of silicon carbide.

Main benefits are: 

  • Long service life
  • Resistance in severe environment
  • High mechanical strength
  • EAC certified

Solutions Dedicated to Distribution or Transmission Cables Sheathes

VARISIL HC and RNC HC voltage limiters are a high-performance products designed to safeguard cable in both distribution and transmission networks. They are intended for utilities and cable manufacturers.

+ VARISILTM HC

VARISIL™ HC is a polymer-housed gapless surge arrester mainly used for single-point bonded sections

+ VARISILTM RNL HC 

RNL HC is a plastic overmoulded non-linear resistor for use inside cross bonding cabinets

 

Professional Services

Ensto is proud to provide high-level customer services for our products, ensuring our customer's operational success. We offer comprehensive commissioning support to help you get started, along with online technical assistance for immediate solutions

Our specialized training programs enhance your team's skills, while our technical expertise ensures you have access to the best advice. Additionally, we provide diploma programs to further deepen the knowledge. With Ensto, you gain a dedicated partner committed to maximizing performance and reliability in your operations. Contact us to learn more about our services for distribution automation. 

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