Wind Power Industry: Low Voltage Ride Through Standards

Recently, for the wind farms and wind turbine manufacturers, the most "main theme" of the work is that the low-voltage ride-through capability has reached the standard.

Under the background of the country's adjustment of the rhythm of the wind power industry, many policies and standards have been introduced, but the requirement for low voltage ride through capability is that “the wind turbines should be able to maintain the grid-connected operation when the voltage at the grid point drops to 20% of rated voltage. Millisecond low-voltage ride-through capability, wind farm connection point voltage can recover to 90% of rated voltage within 2 seconds after the fall occurs, the wind power unit should have the ability to continuously run in grid, so the clear standard is undoubtedly more than any policy Both standards and standards are more direct and simple.

Mainstream companies are actively looking at standards

"This is a good thing." The person in charge of the first and second-tier wind turbine manufacturers interviewed agreed.

An enterprise manager of a wind turbine told the reporter: “We take a positive view of this standard. Although it takes some time and cost to achieve the standard, objectively speaking, every time the capacity of the equipment enterprises is inseparable with the increase in power grid requirements, the requirements of the power grid urge us to Improve core competitiveness."

It is not unreasonable for mainstream wind turbine companies to actively look at the promotion of low voltage ride through standards. At present, grid connection is difficult to be regarded as the biggest constraint for wind power development. The poor quality of wind power is the main reason for grid connection difficulties. A better way to solve this problem is to have a low-voltage ride-through capability for fans and increase the number of hours the fans can be used. Willing to acquire such wind power.

"The standard will eliminate those wind turbine companies that do not have core competitiveness, and increase industry concentration. This is also a good thing for us." A wind turbine company official said that although the low-voltage ride-through capability is not very sophisticated technical requirements, but the industry 20% The small and medium-sized SMEs may not be able to meet the standards. They are currently happy about the vicious price war, and the improvement of standards will be conducive to industry consolidation and will not have a serious impact on the industry.

"Time is tight and tasks are heavy"

It is costly to reach the standard. It is understood that the low-voltage ride-through capability currently proposed, the less work undertaken by wind farms, is mainly due to the time and cost of the entire machine company to undertake the transformation.

Xiang Long, the deputy general manager and chief engineer of Xiangdian Wind Energy Co., Ltd., said: “The time is tight. On the one hand, the batch rebuilding of existing models takes time. On the other hand, the experiment also takes time. However, the direct drive wind turbines are relatively easy to implement.”

Yao Yu, Gold PR Director of Public Relations, told the reporter: “The gold wind adopts advanced direct-drive permanent magnet full-power inverter technology, which has inherent advantages in low-voltage ride through. Previously installed wind turbines did not require owners to have Because of the low voltage ride-through capability, there are currently more than 4,000 installed fans that need to activate this function, and the fans produced will have low voltage ride-through capability. The time and retrofit costs are relatively low."

For time and cost, Li Maosheng, a senior researcher of China Investment Advisors, listed a series of figures for reporters: “For 1.5 MW wind turbines, for example, a direct drive needs to install a module, and the reconstruction time takes two or three days and costs about 100,000 yuan. Left and right; and double-fed models do not have full power conversion, it may take a little longer to transform, the cost of transformation is about 300,000 to 400,000 yuan." But he said that regardless of the direct drive and doubly fed, low voltage ride through There are no technical problems.

Industry expects equal dialogue between generation side and transmission side

In the interview, the fan companies in addition to unanimously welcome the introduction of standards, there is one thing in common, that is when the reference to the standard will be added to the standard an attribute - "grid" standard.

Experts stated that there are two ways to solve wind power grid connection, namely, low-voltage ride-through transformation of wind turbines, or smart grid reform of power grids. “The low-voltage ride-through standard is a standard proposed for the complete machine company. Next, there is also a management requirement for wind farms, and the grid is currently only purchasing this ambiguous requirement in full. It seems that the complete machine company and the wind farm are passive. Fang, and the power grid is the active party.” A fan company official who declined to be named said that at present, the status of the power generation side and the power transmission side is not equal, the standard is the embodiment of the power grid.

In addition, some companies believe that standards such as "low voltage crossing capability capable of maintaining 625 milliseconds of grid-connected operation when grid point voltage drops to 20% of rated voltage" are too stringent in comparison with European and other countries' standards, and the technology of low voltage ride through is mature. However, the higher the standard, the higher the cost, and the power grid does not have to bear the cost, and enjoy it.

Li Maosheng said: “If the smart grid is strong enough, it can also accept relatively low voltages. However, the current smart grid construction spans a long period of time, and the low voltage ride through transformation of wind turbines is indeed the most effective way to solve the problem in the near future. The standard is high and the risk to the power grid and the country is small."

"It is worth noting that at present, low-voltage ride-through testing is conducted at the Zhangbei Testing Center of the State Power Research Institute under the State Grid. As an enterprise, the State Grid serves as both a referee and an athlete. Its credibility is naturally questioned by wind turbine companies. "Li Maosheng said many companies' voices. Some wind turbine companies stated that improving the low-voltage ride-through capability of wind turbines does not pay any cost to the power grid, and the higher the demand, the more favorable to the power grid. Under such circumstances, it can be objectively and impartially observed. “We expect more reliable inspections. Institutions carry out tests."

“Recently, officials from the National Energy Administration stated that in order to better promote the access and consumption of wind power, a clear request will be made for power grid companies. We expect equal demands on the power generation side and the power transmission side.” People say.