"At present, digital relay protection is showing a development trend of high integration, high reliability, and high protection, and the level of informatization is continuously increasing to meet the operating requirements of new energy and microgrid access and other complex grid conditions, as well as being more cost-effective The need for construction and maintenance has become the development direction of the power industry. "Dr. Li Yaping, general manager of Xuchang Cape Test Research Institute Co., Ltd., said at the" 2018 ABB Power and Automation World "exhibition.
Yaping Li, Ph.D., professor-level senior engineer, Chinese standardization expert, chairman of IEC / TC 95 (International Electrotechnical Commission Relay Protection Technical Committee), director of National Relay Protection and Automation Equipment Quality Supervision and Inspection Center, smart microgrid control equipment and system quality Director of the Supervision and Inspection Center, and director of the National Electric Vehicle Charge and Replacement System Quality Supervision and Inspection Center.
Digital relay protection has made great progress
Recently, the "Xi'an power outage" on the hot search list has received widespread attention.
Behind the concerns should be considered whether the first line of defense for the safe operation of power systems-the important role of relay protection.
With the expansion and upgrading of power grid construction and the changing operation of power systems, China's relay protection will move towards a more professional, intelligent, and highly reliable direction; power companies have also put forward higher requirements for relay protection devices. Dr. Li Yaping said, "Under the new operation and maintenance conditions, power grid automation has become a mainstream technology. Relay protection not only plays its core fault tripping role, but also assumes more intelligent and systematic support functions." This is Digital development sets the tone.
In 2003, the IEC 61850 series of standards was released, providing a complete solution for the interconnection and interconnection of intelligent electronic devices (IEDs) in substations. This is the first communication standard dedicated to the comprehensive interoperability of intelligent electronic devices in substations. Based on the IEC 61850 standard, the process layer equipment represented by merged units and intelligent terminals has continued to develop and move towards engineering applications. The analog and switching signals traditionally transmitted to the relay protection via cables have been started by digital signals transmitted by optical fibers. To replace. As a result, digital relay protection has officially entered the stage of history.
Relay protection requires long-term development, which requires "standards first". In the past 10 years as the chairman of IEC / TC 95, Dr. Li Yaping led a national expert team to establish a new relay protection standard system adapted to the smart grid. Amended more than 20 international standards, and promoted the extensive application and development of relay protection with digital characteristics worldwide.
The construction of digital substations has driven the rapid development of the digital relay protection industry. Data show that the number of digital substations in the State Grid has exceeded 21% of existing substations. According to the “State Grid Corporation's Relay Protection Technology Development Outline” newly formulated in 2017, digital protection is about to enter a new stage of “sampling digitization, protection in situ, component protection dedicated network, and information sharing”.
Standardized arc protection enters the fast lane
As the demand for industrial power and residential power continues to increase, the capacity of the power grid continues to increase, the number of substations continues to increase, and the relay protection of switch cabinets in substations is becoming increasingly important.
Compared with the overcurrent and overvoltage short-circuit faults of general equipment, the arc fault inside the switchgear is the fault that has the greatest danger to the safety of operating personnel and equipment in the power system. According to statistics, 75% of internal arc faults involve personnel operations, which will not only cause destructive hazards to the equipment, but also seriously endanger the safety of workers. "In recent years, with the advancement of technology, the development of arc protection has also entered the fast track," said Dr. Li Yaping, "GB / T 14598.302-2016 Arc Protection Device Technical Requirements" and "NB / T 42076-2016 Arc Protection Device" Standards have been issued one after another, and the industry has bright prospects for application.
Dr. Li Yaping said, “At the just-concluded IEC / TC 95 plenary meeting in Frankfurt, Germany, experts from all countries participating in the world unanimously decided to include arc protection into the future digital standard system.” As a pioneer in the research and development of arc protection devices, ABB is based on IEC 61850 The arc protection of GOOSE communication functions and other digital protections have achieved outstanding application performance in the industrial and railway transportation fields, and also contributed to the international standardization of power system relay protection.
Technology frontier digital arc protection scheme is widely used
At the "2018 ABB Power and Automation World" exhibition, ABB showed a digital arc protection scheme. This protection scheme is based on ABB's Relion600 series protection, and a digital protection network is established with IEC61850. Protective devices that act as contacts within the network share data in real time, and also share their judgments about the current state. Therefore, when a fault occurs, it does not rely on a device to determine the fault, but to rely on the sharing of information between the protection to make a judgment. Due to the fast connection of IEC 61850 / GOOSE, while maintaining the same response speed, it has more advantages in terms of cost, reliability, and engineering configuration.
Dr. Yaping Li commented on ABB's digital arc protection scheme: "The arc protection scheme is a new type of relay protection that uses the arc sensor as a criterion to determine the fault and then adopts protective measures to meet the four basic requirements of relay protection, that is, Selectivity, quick-action, sensitivity and reliability of protection. From these points of view, in some special scenarios, the light characteristics can indeed help us find faults earlier and thus isolate faults. At the same time, combined with IEC 61850 The fast and reliable connection allows data to be exchanged between multiple devices quickly, which can further improve the 'four natures' of equipment to judge failures. This is a great innovation and breakthrough. "
At present, the digital arc protection scheme has been successfully applied to Tianjin Beijiang Power Plant (1000MW units), Jingneng Wujianfang Power Plant (1000MW units), and Guangdong Jiahuwan Power Plant (600MW units). In this fast-changing energy world, the safe and stable operation of the power industry is still the top priority of national life. Digital arc protection provides a solid guarantee for safe power consumption and efficient production of industry users and partners with high power guarantee requirements. Relay protection in the digital age adds innovative momentum.