Image Source: Siemens AG

First bullet resistant retrofit ordered for a transformer.


As stated by PTR Principal Analyst Saqib Saeed during the CWIEME conference in Chicago a few weeks ago, bulletproofing is a big topic utilities are dealing with since the Metcalf, California substation attack on April 16, 2013. According to an analysis by the Wall Street Journal, there were 274 cases of vandalism or deliberate damage to power stations between 2012 and 2014 in the United States alone.

Why do grid assets like power transformers in US need physical protection?

Transmission network is designed with enough breathing space to cope with occasional failure of Large Power Transformer (LPT). However, following factors can cause LPTs to be the culprit of widespread network failure:

• Natural disasters spanning a large network area

• A coordinated attack on critical LPTs

• Aged equipment lacking the capability to prevent cascading shutdown

• Misoperation of control and protection

At the moment, the US grid contains risk with the first three factors; so utilities have developed a two-pronged approach to mitigate them. First, replace high-priority power transformers nearing end-of-life with transfomrers equiped with extra physical protection. Second, easy to access back-up power transformers through utility scale equipment sharing program. Sensing this requirement in the netwrok, tier 1 players have turkey solution for physical protection of power transformers.

Siemens actually delivered the first transformer capable of withstanding projectiles back in January of this year. Bullet-resistant transformers are part of Siemens’ Transformers Pretact® concept, which helps transformer operators to prevent failures, protect their assets from harm, and react rapidly in case of an emergency.

They are not alone though in pursuit of this utility need as ABB introduced its AssetShield ballistic protection system in November 2015, winning orders for the offering one year later. What is special about this particular installation relative to others Siemens has done is that it is a retrofit rather than a new installation.

So what exactly does bulletproof mean in relation to a standard transformer?

The important elements involved in bulletproofing includes armor panels to protect the oil tank, radiator, conservator and replacing of porcelain bushings. The issue is that standard transformer tank material i.e. 10mm thick steel sheet can be easily impacted by a VPAM Class 7 bullet, according to Siemens. This is where additional protection by armor panels helps reduce the impact of projectile. For bushings the important change is that porcelain is being replaced by composite, specifically HSP Resin Impregnated Synthetic (RIS). Additional joints also need to be added to allow for ease of access by technicians.

So what does this mean for the Power Transformer market?

PTR expects that this market, currently enjoyed by Tier 1 players, will soon have company from the Tier 2’s as they will add physically strengthened transformers in their portfolios given the large scale replacements planned by utilities. The question remains of what the impact will be to component level maufacturers? We are already observing bullet proof armor manufacturers tailoring their offerings for utilities. Impact on the bushings market is a faster shift towards composite material than previously thought and penetration of bushing monitoring systems in North America market. Additionally, PTR believes that ballistic and weather protection will be further applied to other bulk power substation systems like reactors and circuit breakers in future years.

Link to the press release: here