In the first day of December 2011, the newly-built Beixing 220 kV substation is under intense debugging at the 500 meters east of the 13th team of Beixing Farm, Qitaihe City, Heilongjiang Province, next to Qibao Road. Suddenly, the electronic transformer is suddenly The internal insulation was electrically broken down, and the transformer exploded in an instant.

The Beixing 220 kV substation is one of the first 42 pilot projects for the construction of a smart substation by the State Grid Corporation of China, and is also the first pilot project for the construction of a smart substation in China's first high latitude and cold regions. The total investment of the project is 73.19 million yuan. The electronic transformer explosion at the Beixing 220 kV smart substation is not an isolated phenomenon. According to industry sources, since the autumn of last year, electronic transformers, one of the core components of the first batch of completed demonstration smart substation projects, have been broken down and an explosion has occurred.

State Grid issued a document to strengthen supervision

According to industry sources, transformer explosions occurred in the smart grid substations in Hunan, Yunnan, and Fujian. The electronic transformer manufacturers involved include Nanrui, Xi’an Huawei, and Xinning Optoelectronics.

A related business person, who did not wish to be named, told reporters that the State Grid Corporation of China had done statistics on the problems exposed by all built-in and commissioned smart substation electronic transformers, and the failure rate was as high as 5%. However, this person did not show the 5% data basis, but said that he was heard at an internal meeting of the State Grid System. The source also stated that the State Grid Corporation also analyzed each of the malfunctioning electronic transformers one by one, with different conclusions. For example, the reason why the explosion of the electronic transformer in the Beixing 220 kV substation is not in the manufacturer's NARI, but NARI There are quality problems with the capacitive voltage divider provided by the supplier; Xi'an Huawei and Xinning are caused by their own reasons, but for what reason he does not know it.

A reporter’s “Circular Concerning the Practical Strengthening of the Operation and Management of Electronic Transformers” issued by the company of the State Grid Corporation on January 13, 2012 shows that the State Grid Corporation does have an electronic mutual inductance. The frequent occurrence of device failures is highly vigilant and measures to reduce risks are proposed. The document stated that "in recent years, with the development of the company's smart grid, nearly 2,000 units of various types of electronic transformers have been put into operation. The operation shows that due to the weak design capabilities of some manufacturers, the process controls are not strict, and test equipment is tested. Incomplete, the failure rate of electronic instrument transformers in transport is much higher than that of traditional transformers, which has a certain impact on the safe operation of the power grid." The "Notice" requires all operational subordinates to subordinate companies, "when the relay protection device is not integrated or In most transformations, transformers should not be replaced with electronic ones. Based on the current maturity and cost-effectiveness of electronic transformers, digital transformers of 35 kV and below should not be retrofitted for the time being.” State Grid Corporation's attitude is that the current electronic transformer technology is not yet mature, for safety reasons, some do not need to replace the new electronic transformer is not replaced as much as possible, the traditional transformer performance and stability, reliability, in some The project will be preferred.

Although smart substations are designed to be unattended, based on the current high failure rate of electronic transformers, State Grid Corporation has proposed a number of suggestions to enhance the operation of electronic transformers.

Grid smart grid or slowdown

In the middle of last year, State Grid requested the construction of a smart substation construction site in Changchun to speed up the construction of smart power transmission and transformation projects. Since then, Liu Youwei, deputy director of the Strategic Development Research Center of the China Electric Power Academy, a research institute directly under the State Grid, said in an interview that during the “12th Five-Year Plan” period, the State Grid will establish about 5,000 smart substations nationwide. He explained that the 5,000 seats are not all new, some will be intelligently rebuilt, but "we must intelligently upgrade all the substations to be built."

Shanghai Securities's research report believes that due to the construction of smart substations, by 2020, smart transformers will add a total investment of 350 billion yuan, a total investment of 280 billion yuan for smart switches, and a new total investment of 90 billion yuan for new transformers.

An electronic component manufacturing company executive revealed to reporters that due to the current technical instability of the electronic transformers, the State Grid Corporation may slow down the speed of the smart grid, and for the power grid is always the first security. "In the widespread application of new technologies and new products, large-scale promotion, some problems have been exposed. This time, we need to slow down and think about how to solve these problems."

According to Pan Jimeng, chief engineer of the Liuzhou Bureau of the South Network EHV Transmission Company, all this need not be too worried. “Actually, these problems are not significant. The problem is only a part of the electronic transformer. Now, we should be careful about the application. With the gradual maturity of technology and products, there will certainly be no problem.”

The investment community is still optimistic about the smart grid. Zhou Sili, assistant director of the Northeast Securities Research Institute, believes that the problems will not affect the progress of the entire smart grid investment. The State Grid tender is still on schedule. "Not that transformers can't be done anymore after being bombed several times. This can be improved. For example, ultra high voltage equipment, 5 years ago, don't say UHV, or UHV, we can't do it. Nowadays, there are several large transformer companies in China. Isn't it also doing UHV equipment? It's all running on the grid. We don't have to worry about several accidents. What's the problem? It's not as serious as in the industry. After all, China's manufacturing capabilities are still there." Zhou Sili said .

However, it is worth noting that, not long ago, State Grid Transmission and Distribution announced the first batch of centralized tendering projects in 2012. Although the speed of smart substations is still rapid, the scale of transformer bidding has dropped by 18.04%.