Application of the hottest pass circuit breaker in

Application of pass circuit breaker in 110kV substation

Abstract: This paper introduces the characteristics of pass circuit breaker, and analyzes the safety, reliability and scope of application of this kind of equipment

key words: pass circuit breaker SF6 GIS

overview

plug & switch system is a new intelligent high-voltage circuit breaker introduced abroad in recent years. Its design idea provides a new choice for the development direction of primary electrical equipment in the future, and has broad development prospects. The 110 kV Xiya substation in Zhongshan City, Guangdong Province adopts pass switchgear, which was put into operation in January, 2003, and achieved good operation results. The use of pass combined intelligent electrical equipment can not only meet the stringent requirements of the substation in terms of land occupation, environment and adaptability, but also have high flexibility in the expansion and transformation of the substation. At the same time, it can also reduce the investment of the substation and meet the requirements of energy conservation, consumption reduction and environmental protection. In terms of the development trend of the substation, using pass to build and transform the substation will be a good choice

2 introduction to the characteristics of pass circuit breaker

pass circuit breaker is a combined intelligent electrical equipment, which is composed of primary main equipment, secondary intelligent equipment and process processing and communication interface equipment. Pass circuit breaker is simpler than GIS. It is a fixed configuration structure without outgoing disconnector and grounding knife. There are three kinds of pass products, which are pass M0, pass M1 and pass M2 according to different applicable voltage levels. The Xiya substation adopts pass M0 series, which is three-phase installed on a support

(1) pass is to put the one-phase circuit breaker plus disconnector and grounding switch as a module in the SF6 closed chamber. Each phase has an independent shell, and all operating functions are integrated into one operation box, with few movable elements and compact layout

(2) it inherits the advantages of GIS. The main equipment, operating mechanism and arc extinguishing chamber of pass circuit breaker adopt mature GIS technology to ensure the reliability of the equipment

(3) simplify the equipment and complete all functions with as few components as possible, such as canceling the outgoing line disconnector and grounding knife

(4) intelligent sensor technology and micro processing technology are adopted in the primary equipment to realize the monitoring and diagnosis of the equipment, the monitoring of many kinds of materials of the process axis and the monitoring of the computer in the station through digital communication. From pass circuit breaker to relay protection, measurement and monitoring system, optical cables are used for connection, and there are few secondary cables

(5) the monitoring, automatic state check and defect alarm of primary equipment replace the traditional periodic inspection test and preventive test, and change the periodic inspection to condition based maintenance. The operator can arrange the overhaul and maintenance time according to the equipment operation status and trend analysis results

(6) convenient and fast installation and maintenance. A pass component is equivalent to or almost equivalent to a complete Bay, and the assembly and commissioning of the complete equipment have been carried out in the manufacturer; The installation in the substation can be completed in a short time. It can be directly installed on a smaller platform after being unloaded from the trailer at each interval. It is also replaced as a whole during maintenance, without disassembly and debugging, which reduces the power outage time

3 experience on the operation of pass circuit breaker

(1) interface of relay protection and monitoring equipment at bay level. At present, there is no unified transmission protocol and network standard for substation automation system. At present, the pass circuit breaker only has iec61375 (MVB) process processing bus protocol, and this interface protocol has not been developed for domestic protection devices and station automation devices. Therefore, when it is from a different manufacturer from the relay protection and monitoring system equipment of the Bay layer, its interface needs to convert the transmission protocol. The protection device of pass has particularly high requirements for the real-time and reliability of current and voltage input signal transmission. The effect of protocol conversion will have a direct impact on the reliability, rapidity and flexibility of the protection. When domestic manufacturers independently develop this part of the interface, abb is also required to provide MVB two-way communication protocol and the development environment of man-machine interface software for primary equipment monitoring. Considering the investment scale and other reasons, the 110kV Xiya substation adopts the method of replacing photoelectric current and voltage sensors with conventional current transformers (TV external configuration) in pass circuit breakers and replacing intelligent equipment with conventional switch auxiliary contacts; This method is the most convenient to interface with the existing protection and monitoring equipment, but it also loses part of the performance of photoelectric current and voltage sensors and pass intelligent system

(2) due to its own design reasons, the grounding switch is connected to the circuit breaker side, rather than the usual line side. The manufacturer believes that it is a finalized product and cannot be changed to the line side grounding switch according to the user's requirements. Therefore, the grounding of the equipment or line during operation, maintenance or switching operation needs to pass through the pass circuit breaker, which is different from the traditional custom, so it needs to be carefully considered in the design of the main electrical wiring and the formulation of operation regulations

(3) after more than one year of operation, its operation vibration and noise are small, and no abnormality is found in the partial discharge test

(4) maintenance workload. Routine power outage inspection every 5 years, including lubrication, mechanism gasket, mechanical characteristics and loop resistance; Overhaul is required for every 5000 flash operations or 40ka9 disconnections, or 15 years of operation. The overhaul method provided by the manufacturer is to replace it with pre debugged modules

4 evaluation of the safety and reliability of pass operation

pass device is mainly designed for the safety problems existing in the power system. The aviation industry has been closely studying 'what thermoplastic composites can do for them' and developing it. The main difference between GIS and GIS in terms of safety is that GIS integrates the primary equipment of the whole substation, including circuit breakers, lightning arresters and buses, into several SF6 gas sealed chambers for close connection, but it has a disadvantage. Due to the high integration, once there is a problem with one equipment, the power outage range is large and the loss is relatively large. In addition, because all electrical connections are carried out at the substation site, it is difficult to ensure the process requirements due to environmental constraints, which correspondingly increases the hidden danger of accidents. For example, the most common air leakage problem, due to its large area, is difficult to find the fault point, which increases the difficulty of power outage maintenance and prolongs the time of power outage. Pass takes the one-phase circuit breaker, disconnector and grounding switch as a module and puts them in the SF6 closed warehouse. Each time there is an independent shell, the assembly and commissioning of the complete set of equipment have been carried out in the manufacturer. The on-site installation and commissioning are relatively simple, and its reliability and flexibility are relatively high. At the same time, for pass, if there is a problem with any phase, it will replace that phase, reducing the scope of power failure and maintenance time; Moreover, the modular production process makes it more earthquake resistant and safe to operate

5 economic evaluation of pass scheme

if it is calculated according to the same imported equipment or the same domestic equipment, the price of pass equipment and the supporting equipment of the corresponding substation is cheaper than GIS, and the regular equipment is expensive. However, because the pass currently used in China is imported from abroad, its equipment price is significantly higher than that of GIS equipment produced in China; It is expected that after the mass production of pass equipment by domestic manufacturers, its price will have advantages over GIS

6 the adaptive range of pass

(1) because AIS is insulated by air, and pass is insulated by SF6 gas, the floor area will be greatly reduced, which saves 60% of the space than AIS substation; Taking advantage of the characteristics that pass can operate outdoors, when the land acquisition cost is high and the investment cost is controlled, pass can be installed on the roof of the main control building of the substation, which not only avoids the acquisition of high-voltage field land, but also saves the cost of purchasing expensive GIS equipment

(2) in view of the high reliability and flexibility of pass, it is convenient to repair and replace equipment in case of failure, which relatively reduces the scope of power failure and maintenance time. When it is responsible for power supply in important areas of the city and the scope of land acquisition of substations is limited, ass, which is directly counted by p China Coal Industry Association, is an ideal choice for 90 large coal enterprises with sharply shrinking profits

(3) using the overhead form, it is installed beside the street in the heavily loaded area

7 conclusion

the introduction of pass circuit breaker has changed the construction, operation and maintenance mode of traditional substation projects, and provided a new thinking mode of less investment, high efficiency, improved reliability, less maintenance and unattended management mode. However, there is no other precedent to use for reference when it is cited in the 110 kV substation project, so whether in construction, research and development, design or construction, operation and maintenance, it is necessary to carefully analyze and deeply study these topics, such as secondary and system configuration, interface and switching operation, from the perspective of safe and reliable operation of the system. (end)