More intelligent,active and reliable distribution network is the focus of the construction of power grid companies at present,among which on-line monitoring of distribution network,fault alarm,active repair and line loss management are the most important parts of research and development and construction.Infrastructure such as smart meters play an important role in it.
On the basis of existing basic equipment,how to improve the automation level of distribution network better,and assist the daily management,monitoring,operation and maintenance of distribution network,rush repairs,in this regard,all parts of the country are studying and have achieved a stage of results.
Development of a new modular acquisition terminal
The 2009 edition of electricity information acquisition terminal is currently in operation,although it makes the manual meter reading step out of the historical stage,makes the meter reading data more accurate,and can simply analyze the collected electricity data.However,in the face of the higher and higher requirements for the acquisition system,the 2009 version of the power information acquisition terminal gradually fails to meet the requirements.
In view of this,the Metrology Institute of the Chinese Academy of Electrical Sciences has designed a new modular power information acquisition terminal,which adopts high-speed communication,Beidou and GPS double satellite positioning,eSIM and other more efficient and reliable communication technologies.It can expand the active reporting function of low-voltage household meter blackouts,improve the reliability and stability of the time-service system,and maintain the reliability and stability of the system more accurately.Qualitative analysis can more accurately maintain the user's meter relationship files,realize the user's power supply circuit impedance monitoring and reliable identity authentication.It is expected that the operation and maintenance cost of the site can be greatly reduced and the intelligent management of the distribution station area can be effectively assisted.
Upgrading Intelligent Meter
Smart meters will play an increasingly important role in smart grid in the future,such as the management of distribution stations.Since 2017,many provincial companies have made active reporting of blackouts.Among them,supercapacitors have been installed in the module of watt-hour meters.
In 2018,the LST Gasp smart meter integrated with supercapacitors was finally born in Hangzhou,and 100,000 Last Gasp smart meters were installed by the end of September 2018.In the instant of low-voltage blackout,100,000 Last Gasp smart meters can use the"last breath"stored in the supercapacitor to mean"failure!"The data is sent to the main station of distribution automation.In the distribution network control center,it can quickly synthesize the"rescue signal"from different meters,accurately locate the fault location,and arrive at the scene for emergency repair at the first time.
Redesign Distribution Network Architecture
Due to historical and objective reasons,domestic distribution network planning is relatively backward.Although the redesign of the distribution network structure is the"root cause",the technology and manpower and material resources required are huge,just like urban planning and transportation,Beijing,as a first-tier city in China,is still facing"day and night"congestion.So it sounds simple,but the actual implementation of the redesign plan is quite difficult.
Recently,Huizhou Zhongkai Power Supply Bureau has innovatively built a"well-shaped"intelligent double-loop network to achieve sectional and zonal isolation of faults,shorten the blackout scope and accurate fault location,achieve self-healing function,meet the N-2 mode of operation,realize unmanned patrol monitoring and intensive intelligent power consumption system,save investment and human costs of operation and maintenance.
According to Zheng Zhaodian,head of the distribution network planning working group of the production planning department of Huizhou Zhongkai Bureau,the"well-shaped"connection refers to that in the distribution network,a closed-loop network is outgoing from two substations,and the closed-loop network is also connected to form a well-shaped network to realize the user's N-2 operation mode.N-2 means that under normal circumstances,there are N-circuit lines to supply power to the region.If the power supply of two circuits is reduced in the case of failure or planned outage,it can still meet the need of power failure in the region.Compared with the main distribution network connection mode of Guangdong power grid at present,the well-shaped intelligent double-loop network is specially designed to achieve higher power supply reliability for high-tech manufacturing enterprises;compared with other types of distribution ring network at present,the structure of Zhongkai's well-shaped intelligent double-loop network is relatively simple and effective in fault fast positioning,fault isolation and self-healing function logic,which is convenient for construction and operation and maintenance.It can save construction cost and manpower cost of operation and maintenance for power supply enterprises.
Business Expansion by High Speed Communication
Of the existing power communication modes of hundreds of millions of power users in China,70%of the local communication modes adopt narrowband power line carrier communication technology(10kHz~500KHz).The communication speed of low-speed communication mode is slow and the success rate of automatic acquisition is low.On-line monitoring,fault alarm,active repair and line loss management of distribution network need high-speed,real-time,a large number of information transmission,and the voice of high-speed communication is increasing.High-speed wireless communication and high-speed carrier communication technology raise the transmission rate of power information acquisition system to the level of M bit/s,which can realize high-frequency data acquisition and transmission of power information,enrich the large database of power information,help deepen the application of large data,and realize business expansion.
Based on high-speed communication,the whole data of the whole station can be collected,and the distribution station can be monitored comprehensively.In July 2018,Hubei Electric Power Company of China National Grid innovatively developed a real-time monitoring platform for distribution stations based on data mining and application of electric power acquisition system.The platform fully excavates the existing functions of the concentrator in the station area,real-time monitoring of off-line and out-of-line,line out-of-line and out-of-line,and displaying the alteration of the station area by on-line tables and graphs.The platform can discover the weak links of distribution network operation in time,pre-judge and carry out active maintenance in advance,so as to ensure the safe operation of the grid.It can also effectively monitor the operation status of the distribution network,optimize the operation mode and reduce the line loss rate.