Tridelta Meidensha Surge Arresters

Best solution and superior quality for every requirement

  • Comprehensive product portfolio
  • Stable continuous duty and lowest failure rates ensuring a long service life
  • Best protection levels and bending strength
  • Efficiency and the highest quality in manufacturing


Tridelta Meidensha GmbH provides arresters for every requirement. Our products are specially developed for service in all environmental conditions around the world. They are successfully installed in coastal and desert regions, in areas with high industrial air pollution, heavy wind load, and extreme climatic conditions, seismic zones, and other areas that require special protection.

TRIDELTA arresters protect outdoor equipment such as transformers, motors, generators, traction vehicles, or other equipment from atmospheric and switching overvoltages.

Furthermore, Tridelta Meidensha GmbH provides surge arresters for special applications:


  •  Arresters for capacitor banks in static compensators
  •  AC and DC railway arresters
  •  Arresters for indoor applications in MV cubicles

In addition Tridelta Meidensha GmbH offers an extensive range of transmission online arresters – a cost-effective solution to protect overhead transmission lines, reduce potential line outages and enhance system reliability. A wide range of porcelain and polymer housings in various designs and versions is the basis to provide the optimum surge arrester for every application.

Fast, flexible and customer-oriented

The Tridelta Meidensha GmbH, since 2015 being part of MeidenshaGroup/Japan, has more than 50 years of experience and is specialized in producing high-quality surge arresters. Tridelta Meidensha GmbH is an ideal partner not only for utilities but also for contractors and EPC ́s looking for products from an independent source.


Tridelta Meidensha GmbH stands for fast, flexible, and customer-oriented solutions. As a result of the stable continuous duty, the long lifetime, the low failure rate, and a very good price-performance ratio of our surge arresters, Tridelta Mei-Densha GmbH is one of the leading surge arrester manufacturers worldwide.


The TRIDELTA surge arrester portfolio covers all areas of application, no matter which environmental conditions the surge arresters need to withstand. Based on high technical knowledge new innovative products are added constantly to the portfolio.

MOV blocks –The heart of reliability

Metal Oxide Varistor (MOV) blocks are the heart of surge arresters. They define the electrical properties and the protective function of a surge arrester. Since 2015 Tridelta Meidensha GmbH is part of the Meidensha Group/Japan, the first company that introduced the concept of MOV blocks to the market more than 40 years ago. Since then Meidensha Corporation as well as other leading manufacturers supply their MOV blocks to Tridelta Meidensha GmbH.

Our supplier's know-how in developing and manufacturing MOV blocks leads to high quality arresters with excellent energy absorption capability and best protective levels ensuring a long lifetime of TRIDELTA surge arresters.

High Voltage Surge Arresters with Silicone Housing

  • Three different designs for applications with standard, advanced or highest technical requirements
  • Outstanding pollution performance
  • Resistance to tracking erosion and UV radiation
  • Fire retardant and self-extinguishing
  • Lifetime hydrophobicity

Tridelta Meidensha GmbH offers three different arrester designs for high voltage applications with silicone housing for standard, advanced, and highest technical requirements:
Solid Core, Cage, and Tube Design. They all use high-quality silicone as insulation material with outstanding pollution performance. All three of the designs benefit from important silicone properties such as resistance to tracking erosion and UV radiation, being fire retardant and self-extinguishing plus being water-repellent. Genuine silicone rubber housings, compared to other polymeric materials, retain their hydrophobicity during the lifetime of the arrester. This results in the long service life of all TRIDELTA arresters with silicone housings.


All three of the designs use the same high-quality MOV blocks ensuring excellent electrical performance. They benefit from easy transportation and installation thanks to their reduced weight compared to porcelain arresters. The differences between these three product lines are their internal design and the method of fixing the column of MOV blocks into the housing of the arrester. Please refer to the next page for more details.

Mechanical stability is given by a solid core of prefabricated modules of fiberglass reinforced woven structure ensuring mechanical stability of the arrester for standard requirements.

A cage of FRP rods around the stack of MOV block, fixed into the terminals by a patented wedge clamping system, ensures higher mechanical strength for advanced requirements.

A FRP tube with enclosed gas volume, including a pressure relief device, ensures the greatest possible mechanical strength, for the highest mechanical requirements, i. e. for areas with high seismic activity, heavy wind load, extreme climatic conditions, or additional mechanical loads.

Solid Core design:

Cage design:

Tube design

MOV blocks are pre-arranged in „Solid Design Modules“, prefabricated modules of a fiberglass reinforced woven structure with silicone sheds ensure high flexibility regarding customer demands

Network Voltage Um: up to 170 kV*

Weight: very low weight


Mechanical strength (SSL): 1,1 kNm


Key Parameters:

  •  Short delivery time
  •  Easy transport (also in horizontal position) reduce     transportation costs
  •  Easy and fast installation without special equipment






  •  For standard mechanical requirements
  •  Excellent for line arrester applications (NGLA and EGLA type)



  • Competitive arrester for applications with standard/basic mechanical requirements
  •  For applications up to 170 kV networks

Cage of FRP rods around MOV blocks, FRP rods fixed into the end terminals by a patented wedge clamping; silicone sheds directly molded onto MOV blocks/cage, no enclosed gas volume, no sealing/pressure relief device needed
up to 420 kV*

lower weight than tube


up to 4 kNm


Key Parameters:

high safety margin regarding electrical and mechanical overloads

  • No violent destruction after an overload or short circuit events
  • Shorter than tube design
  • Easy transport (also in horizontal position) reduced transportation costs
  • Easy and fast installation without special equipment



  • for standard and advanced mechanical requirements
  • excellent for line arrester applications (NGLA and EGLA type)



  • Arrester with the best price/performance ratio
  • For applications with advanced mechanical requirements
  • For applications up to 420 kV networks

FRP tube with enclosed gas volume (hollow insulator),
silicone sheds directly moulded onto FRP tube

up to 800 kV

lower weight than comparable porcelain


up to 23 kNm


Key Parameters:

  • Excellent pollution behaviour due to highly hydrophobic behaviour of silicone
  • Highest safety margin regarding electrical and mechanical overloads, no ejection of internal parts in case of short circuit
  • Even after short circuit/pressure relief remains 75% of mechanical stability
  • Delivery time similar to porcelain arresters
  • Easier transport than porcelain arresters
    (less risk of damage)
  • Installation similar to porcelain arresters but
    lower weight



  • For the highest mechanical and safety requirements 
  • For arrester applications as support/post insulator
  • For applications with seismic requirement



  • arrester for applications with the highest requirements to mechanical strength and safety

High Voltage Surge Arresters up to 800 kV

Medium Voltage Metal Oxide Surge Arresters up to 51 kV

High Voltage Surge Arresters for GIS up to 500 kV

Meidensha Corporation, headquartered in Tokyo, Japan, is an electrical equipment manufacturer and with an extensive product portfolio, ranging from power generation, transmission, and distribution and control systems for electric utilities and railways, to motors and controls for various industrial applications. The company was founded in 1897 and now operates manufacturing facilities in Japan, China, Singapore, Thailand, and India.

Meidensha’s innovative spirits have produced many new technologies, including the development of epoch-making metal oxide gapless surge arresters for electric power systems in 1975. This has set new industry standards for the protection of power equipment and was awarded an IEEE Milestone in 2014. Meidensha has since then been a world leader in surge arrester technologies and a global supplier of surge arresters as well as high-quality, high-performance metal oxide blocks (metal oxide varistors) to surge arrester manufacturers in various countries for use in their products, helping to protect power equipment in every corner of the world.

Monitoring Equipment

Tridelta Meidensha GmbH R&D and HV Test Laboratory – Investment in the future!

The combination of continuous development for our products and investment into modern high voltage test facilities specialized for surge arresters is one key factor for the success of Tridelta Meidensha GmbH. Based on constant interaction between development and production we are continuously improving our manufacturing lines ensuring a high standard of our arresters. Our development processes are certified according to ISO 9001. Each MOV block and surge arrester is individually tested during and at the end of the manufacturing process.

Our modern and powerful high voltage laboratory is equipped with:

  • Impulse Generator up to 1.200 kV
  • Power Frequency Transformer 600 kV
  • High Current Impulse Generator 150 kA
  • Long Duration Current Impulse Generator for line discharge classes 1 to 5
  • Test Facilities for 5000h weather aging test
  • Climate testing laboratory with the capability of -40°C ... +100°C
  • Mechanical Bending and Tensile Test machine with the capability of up to 30.000 Nm for bending moment and up to 50.000 N for tensile strength tests

Tridelta Meidensha GmbH is able to conduct most of the usual type tests as well as acceptance tests and tests for R&D activities.

In addition to our wide range of surge arresters, we offer devices for monitoring and recording the discharge process and the condition of the arrester.

SmartCOUNT is an intelligent surge arrester monitoring system. smartCOUNT can measure leakage current as well as impulse currents fully automatically and can deliver a trend curve on a website.

Our Surge Counter DCC2 provides information about the number of
events. With model DCC-M2 you can also check the total leakage current.

The Monitoring Spark Gap is a device to provide information about the type and energy of discharge events.

TRIDELTA Quality Products Made in Germany

Our arresters are manufactured in Hermsdorf, Germany. German art of engineering, best materials and approved testing technologies make TRIDELTA arresters a synonym for quality. Our tradition and knowledge over decades, the innovative potential of our engineers and employees, and our uncompromising quality demands lead to outstanding products and the best solutions.


Tridelta Meidensha GmbH has implemented a process-oriented quality management system according to DIN ISO EN 9001. The system, all processes, technologies, procedures, and activities are described in our QA manual, process instructions, and related operating instructions.


These documents define the requirements of all business processes, in particular, quality planning and the development, manufacturing, and testing of high-quality products. To ensure that every customer can rely on the high quality of our products, all arresters are manufactured and extensively routine-tested during and at the end of the manufacturing process in compliance with IEC 60099-4.


The very low failure rates of our arresters resulting in their long service life are confirmation to us of our efforts to constantly maintain the highest quality standards for our products.