Meidensha: Creating a better future with our people and technology.

This content is a reprint of "Meidensha: Creating a better future with our people and technology"
that was posted in the Nikkei Online Edition from December 2018 to February 2019.

Meidensha: Creating a better future with our people and technology.

This content is a reprint of "Meidensha: Creating a better future with our people and technology"
that was posted in the Nikkei Online Edition from December 2018 to February 2019.

Stage7 Protecting the Power Grid from the Threat of Lightning Strikes World-class Surge Arresters Prevent Power Outages Caused by Lightning Strikes No Damage Caused to Power Facilities after 28 Multiple Lightning StrikesStage7 Protecting the Power Grid from the Threat of Lightning Strikes World-class Surge Arresters Prevent Power Outages Caused by Lightning Strikes No Damage Caused to Power Facilities after 28 Multiple Lightning Strikes

In the summer of 2018, the Japanese archipelago was struck by intense torrential rains and lightning strikes. In mid-August, the impact of local heavy rains and lightning strikes caused as many as 16,700 households to lose power across Tokyo, Kanagawa and Shizuoka. Later in the same month, lightning strikes cut power supplies to about 7,700 households in Tokyo. Public transportation was also affected with some train services being suspended for an hour and a half. The damage does not end with summer; winter also sees its share of accidents caused by lightning strikes. Damage to equipment in the power grid from lightning can lead to large-scale power outages. Over the course of a year, global warming and other factors have given rise to abnormal weather, and damage from lightning strikes is increasing. Surge arresters, which bring together cutting-edge technology for protecting the power grid from the threat of lightning strikes, are gaining attention in both advanced and developing countries.

Atsushi Sawada, General Manager of the SORESTER Factory, part of Meidensha's T&D Business Unit, says that, "Power outages and other damage from lightning strikes are increasing both at home and abroad. When lightning strikes substations, power transmission lines and elsewhere, it can cause damage to transformers, switchgear and other equipment essential to power supply. This is why surge arresters are installed on each equipment."

A veteran in this field, Meidensha has been producing surge arresters for more than 100 years. These have been supplied to power companies and others under the brand name SORESTER. Sawada belongs to the Numazu Works (in Numazu, Shizuoka Prefecture), which serves as the so-called "mother factory" for factories in China and Germany. Meidensha thus has three sites for the manufacture and development of surge arresters. Sawada is now active as an engineer in Japan, but he also worked in China for eight years. There, he was busy mainly with technology transfers, though initially, he notes, communicating with the local workers was a big challenge. Even after returning to the Numazu Works, he continues to travel regularly to China and Germany, acting as a liaison for the mutual partnership between the three sites.

Atsushi Sawada
Atsushi SawadaSORESTER Factory
T&D Business Unit

Those technology transfers have begun to produce results. "In one case outside Japan, a power facility that have our Group's surge arresters installed was struck by multiple lightning strikes 28 times, but was able to avoid any problems with their power equipment," Sawada says proudly. Meidensha had also already developed surge arresters for power transmission lines more than 30 years ago. Today, with advances in information and communication technology (ICT), digital devices have spread to every corner of society. Power outages and instantaneous voltage drops caused by lightning strikes on power transmission lines can cause enormous damage. Surge arresters which protect power transmission lines have been highly effective in controlling such voltage fluctuations.

At three sites in Japan, China and Germany, Meidensha produces surge arresters that protect power facilities from lightning strikes
At three sites in Japan, China and Germany, Meidensha produces surge arresters that protect power facilities from lightning strikes

"Establishing a Global Standard Technology
Lighter, more compact design has reduced
the volume by 44%"

A surge arrester is a piece of electrical equipment comprising zinc oxide (ZnO) blocks and a ceramic or polymer insulator, and normally does not conduct electricity. With an incursion of overvoltage caused by lightning or others, however, they immediately enter a conductive state, serving to protect electrical equipment by discharging current to the earth and cutting excessive overvoltage. They also have the properties of a semiconductor, returning to their insulating state after discharging the electrical current to the earth.

How are these surge arresters manufactured? We visited a factory dedicated to their production at the Numazu Works.

Entering the factory, the first thing you hear is a deafening roar. Masayuki Takada of T&D Business Unit's SORESTER Engineering Department, observing the waveforms on a measuring device, says, "I'm conducting a tolerance test by sending a 100 kiloampere (kA) current through ZnO blocks, representing lightning striking a power system. We do this because quality is the top priority." Through repeated testing, Meidensha works to improve the quality of its surge arresters. In fact, a remarkable feat was achieved at this factory.

In the 1970s, they were the first in the world to develop a Gapless Metal Oxide Surge Arrester (MOSA) incorporating ZnO blocks which could withstand continuous multiple lightning strikes. Today, it continues to be an industry-standard product both in and outside Japan.

Currently, Meidensha is pursuing lighter, more compact products. Takada explains, "Since we need to be able to install surge arresters in various locations within a power facility, making them more compact is essential. There are environmental problems to consider, and because Japan experiences frequent earthquakes, we need to provide high-quality products that are small, light and durable."

Masayuki Takada
Masayuki TakadaDevelopment Section
SORESTER Engineering Department

In the factory, ZnO blocks are produced as though luxury ceramics are being made. Minute adjustments are made to the raw materials. They are mixed and then fired at temperatures at 1,000°C or higher, and then receive an advanced insulation coating. Takada enthusiastically says, "We need to modify and improve this complex manufacturing process on a daily basis." Based on what he learned in college, Takada has built up his craftsmanship.

We lifted one ZnO block, the size of the palm of a hand, and it turned out to be surprisingly heavy. Takada showed us two blocks of different diameters and began explaining. He said the smaller of the two was a high-performance ZnO block developed in 2015. "Actually, both of these ZnO blocks are capable of absorbing the same amount of energy, but this one has been reduced in volume by more than 40% compared to conventional ZnO blocks with the diameter having been reduced from 64 mm to 48 mm,” he emphasized.

ZnO blocks that go into surge arresters,
Meidensha continues working to make them even smaller.

Utilizing our Strengths as a Manufacturer of Heavy Electrical Equipment To Offer Customers the Optimal Products

Meidensha has one other major strength. Takada emphasizes this, noting, "When developing ZnO blocks and surge arresters for a particular customer, we don't think of the products on a stand-alone basis. Rather, we examine the specifications of the substation as a whole, and consider what kind of ZnO blocks will best fit. Our strength lies in not simply responding to a customer's needs, but in leveraging our stock of knowledge as a manufacturer of heavy electrical equipment to offer the customer the ideal combination of block thickness and performance." Meidensha is highly trusted by power companies and other customers because the company can make a proposal in consideration of the entire power system that includes not only surge arresters, but transformers, switchgear, and other equipment.

Further, by combining their ZnO blocks--the embodiment of ceramics technology--with the electrical technology Meidensha have accumulated as a heavy electrical equipment manufacturer, the company is able to provide surge arresters that meet the needs of the market. Today, as part of its overseas power equipment business, Meidensha is working to build a global structure that will allow it to have a grasp of issues with electric power equipment overall, and work closely with customers to provide solutions.

"Transferring Technology
from Japan to China
Taking a Major Lead over Local Manufacturers"

In China, which today is the world's largest consumer of power, new power plants, substations and other electric power facilities continue to be built one after another. In 2004, Meidensha established MEIDEN ZHENGZHOU ELECTRIC CO., LTD. (MZE) in Zhengzhou, a city in Henan Province, which is said to be the cradle of Yellow River civilization. MZE has become a major site for mass production of surge arresters and ZnO blocks for up to 500 kilovolt (kV) systems.

A growing number of small-scale substations are being built mainly in urban areas in China. This is why one of MZE's main products is surge arresters for switchgear that require less installation space for such substations. Ma Aiqian, Vice Chief Engineer and Senior Manager of Development Department at MZE, says that, "By reducing the height of ZnO blocks for switchgear by half, we have succeeded in creating a more compact surge arrester. This has reduced the amount of gas used in this type of switchgear and has also contributed to global environmental measures." This gives MZE a significant lead over local Chinese manufacturers in terms of producing more compact, environmentally friendly products.

Ma Aiqian
Ma AiqianDevelopment Department

"We at MZE have been very thorough in incorporating Japanese technology and quality control systems, and the ZnO blocks and surge arresters we manufacture are on par with Japan's in terms of quality. We are also focusing on education both in and outside the company, and in new product development, we also exchange technology with Japan and hold regular development conferences among our three sites in China, Japan and Germany," Ms. Ma explains.

Sawada, who spent many years in China and was involved in human resource development and technology transfer to China, says, "To respond to the high expectations of the market, it is essential that we enhance the capabilities of our local production staff. We are now hosting two Chinese engineers at our Numazu Works for training."

The MZE factory in China,
a major site for mass production of surge arresters and ZnO blocks.

"Aiming to Become Number One in the World
Through Synergies Between Sites in Japan,
China and Germany"

The Group's other site is TRIDELTA MEIDENSHA GmbH (TMG), a venerable German manufacturer of surge arresters that was founded in 1889 and joined the Meiden Group in 2015. Started as a manufacturer of ceramic dinnerware, the company immediately switched to producing porcelain for electrical use, and in the 1960s began producing surge arresters. Today, it has grown to manufacture 8,000 high-voltage surge arresters per year. Its sales network has expanded to include distributors and agents in more than 80 countries, delivering surge arresters in more than 120 countries.

Ranking among Europe's largest heavy electrical equipment companies in the field of surge arresters, TMG has continued to refine its surge arrester manufacturing technology and expand its sales network overseas. "We procure low-cost components from around the world, and have strong assembly capabilities. With our global competitors nearby, we are able to catch on to market trends more quickly, and can rapidly put that information to use in developing products." So says Karsten Laue, Head of R&D Department at TMG. TMG is highly regarded in the market for its ability to offer a stable supply of surge arresters with world-class price competitiveness.

Sawada notes, "Taking advantage of TMG's purchasing power, we hope to move forward with joint procurement as well." While the Numazu Works focuses primarily on manufacturing surge arresters for the domestic market, Sawada says that, "Numazu is also the center of competence for R&D and production technology of surge arresters centering on ZnO blocks, so our most important mission is to transfer such technology to MZE and TMG." By creating synergies through the mutual partnership between its sites in Japan, China and Germany, Meidensha aims to become the world's leading manufacturer in the field of surge arresters.

Karsten Laue
Karsten LaueR&D Department

In fact, even in developed countries such as Germany and other countries in Europe, power outages are so frequent that they have become a social issue. If a power outage occurs, smartphones and PCs will cease to work, and the Internet-based society will no longer function. As abnormal weather occurs on a global scale, the engineers at Meidensha are busier than ever, working to resolve issues at the regional level.


Surge arresters now have a history of more than a century, and today many manufacturers compete for business both in and outside Japan. Sawada continues, "Our mission is to provide surge arresters to protect the power grid as it spreads worldwide. In other words, we are protecting peoples' day-to-day lives. We want to not only pursue greater performance in our individual products, but to continue creating surge arresters that are ideal for the market by taking advantage of our strengths in electrical technology and expertise as a manufacturer of heavy electrical equipment" Power consumption continues to increase in developing countries, and demand is growing for power systems ranging from distribution voltage to ultra-high voltage systems. Advanced countries, meanwhile, are looking for lighter, more compact surge arresters that offer superior seismic resistance, safety and environmental performance. This will mean an even bigger role for Meidensha.

Meidensha surge arresters

Meidensha surge arresters

Explanation of terms

Gapless Metal Oxide Surge Arrester (MOSA)
A surge arrester incorporating zinc oxide blocks. In 1975, Meidensha became the first in the world to develop this technology. It dramatically improved the performance of surge arresters in terms of multiple lightning strikes withstand capability and anti-contamination performance, both considered weak points in conventional surge arresters, and has since become the predominant technology for surge arresters manufactured around the world today. It was also recognized with an IEEE Milestone award in 2014, which honors historical achievements in the field of electricity and electronics technology and related fields. This was the first time the award has been given to a Japanese company for an individual heavy electrical product.
*Honorifics omitted.

Meidensha: Creating a better future with our people and technology.

  • Stage1 Powering the excitement.
  • Stage2 Protecting water resources and infrastructure that nurture the community.
  • Stage3 Driving force for a new automotive era.
  • Stage4 Pursuing greater safety and stability in railway transportation.
  • Stage5 AI for water treatment protection.
  • Stage6 Efficient energy management.
  • Stage7 Lightning Protection.
  • Stage8 IoT to protect from heavy rain.
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