Popularization of power grid knowledge

1. What is the role of smart grid?

A: smart grid is based on strong grid structure, supported by communication information platform and intelligent control, including all links of power generation, transmission, transformation, distribution, power consumption and dispatching of power system, covering all voltage levels, and realizing the highly integrated integration of "power flow, information flow and business flow". It is strong, reliable, cost-effective, clean and environment-friendly Transparent, open, friendly and interactive modern power grid.

2. What is power user information acquisition system?

A: the power user information acquisition system is a system that collects, processes and monitors the power consumption information of all kinds of power users in the province in real time.

3. What is an intelligent community?

A: it refers to the intellectualization of power consumption management and service in a relatively independent and unified management community, integrating smart community management system, smart home system, smart charging room, distributed energy access / storage, user energy efficiency management, intelligent business services and other contents. In the near future, when users click the mouse in the office, the washing machine at home will start washing clothes, the electric water heater will run, the hot water for bathing will be ready, the rice cooker will start cooking, and the air conditioner will be turned on in advance to make you cool when you enter the house... These are not science fiction scenes, but will become a reality.

4. Why replace the smart meter? What are the benefits of installing a smart meter?

A: at present, most electric energy meters used by electric customers are mechanical electric energy meters or electronic electric energy meters with single function. Intelligent electric meter has the functions of electric energy measurement, information storage and processing, real-time monitoring, automatic control, information interaction and so on. It is the most important measuring instrument to realize the automation and intelligence of electric energy information acquisition.

Smart meters record the real-time power consumption at home, and residents can query the daily power consumption details of the previous day or recent days through the network. Through the real-time query of electricity, it can also help residents calculate the power consumption of relevant electrical equipment at home, and "find out the" big "consumers of electricity at home, so as to make residents use electrical appliances more reasonably and achieve the purpose of energy saving. It is estimated that when users actively select and optimize the power consumption mode, the peak load can be reduced by more than 15% and the total demand can be reduced by more than 10%.

In case of abnormal power failure of a residential building, the smart meter can feed back to the power supply company through the acquisition system to accurately locate the fault point and further shorten the power failure repair time of the power supply company.

The smart meter can realize automatic meter reading through the acquisition system, improve the accuracy of meter reading, reduce the disturbance to customers, find the abnormality of the meter in time, and avoid the loss and dispute of electricity charge caused by metering failure.

5. What are the functions of smart meters?

A: in addition to the functions of electric energy measurement, information storage and processing, real-time monitoring, automatic control and information interaction, the smart meter also supports the actual needs of two-way measurement, step price, time-of-use price and peak valley price. It is also the technical basis for realizing distributed power measurement, two-way interactive service, smart home and smart community.

6. What is the difference between a smart meter and an ordinary meter?

A: (1) compared with previous electric energy meters, smart meters have added new functions such as measurement information management, power consumption information management and power consumption monitoring, which can better provide customers with accurate and timely electricity charge calculation.

(2) With the function of two-way measurement, it supports the utilization of distributed energy. In addition to recording the amount of electricity entering the user, it can also record the amount of electricity provided by the user to the power grid. If users build their own distributed clean energy power generation facilities such as wind energy and solar energy, when the generated power can not be used by themselves, the excess power can be transmitted to the power grid, so as to save energy and environmental protection, reduce carbon dioxide emission, reduce the carbonization of users' life, and improve the economic benefits of users.

7. What are the principles for power supply companies to replace smart meters? Which customers can replace the smart meter? Are urban and rural customers OK? What is the installation scope?

A: (1) principle: after June 2010, all newly installed users will install smart meters; For electric energy meters that have been used for more than 7 years, gradually replace them with intelligent electric energy meters; For some ordinary electric energy meters without RS485 interface, gradually replace them with intelligent electric energy meters with RS485 interface to realize remote acquisition.

8. Is there a charge for installing / replacing smart meters?

A: in the whole process of smart grid construction and transformation, the State Grid Corporation of China will replace smart meters for all power customers free of charge.

9. Can I apply to install / replace the smart meter by myself? How to handle it? If not, what is the installation / replacement process of the power supply company?

A: replacement process: power enterprises will inform users who want to replace smart meters XX days in advance, and will post or issue relevant power outage notices. For the community where smart meters are to be replaced, the relevant departments of power enterprises will make plans, strive to complete the installation / replacement of smart meters in relevant sections in the shortest time, and try their best to minimize the inconvenience caused by power failure.

10. Application of charge control smart meter in power grid

With the continuous development of the national economy and the rapid improvement of people's quality of life, the demand for electricity is also increasing. However, the current management of residential power consumption is too backward. For many years, the traditional operation mode of power consumption first, meter reading and then payment has been adopted. According to statistics, there are tens of thousands of meter reading teams in the power sector alone, and the manual meter reading method has low work efficiency and high labor intensity. In addition, there will be problems such as inadequate meter reading, estimation, omission, wrong reading, wrong calculation and long meter reading cycle, which makes it impossible to talk about the prevention and control of power theft. With the society moving towards informatization, networking and the modernization of power system, manual meter reading has become a major obstacle restricting the modern management of power supply system. In terms of the integrity of the system, the power system has basically realized network management from power generation, distribution and transmission to the regional substation, but the user terminal is not connected to the network, resulting in the incompleteness of the system and directly or indirectly affecting the exertion of the potential of the system. It has caused a great waste of manpower, material resources and time to the power supply management department. In order to meet the needs of society and ensure users to use electricity safely, reasonably and conveniently, the traditional electricity meter and electricity management mode are transformed to meet the needs of social development.

Because of the above background, intelligent watt hour meter came into being. The so-called smart meter is to apply computer technology and communication technology to form a watt hour meter with smart chip (such as CPU) as the core, data collector and remote meter reading system, which has the functions of electric power measurement, timing, fee recording, communication with host computer, power consumption management and so on.

11. Classification of intelligent watt hour meter

As the measurement basis of electricity charge, electric energy meter involves a meter reading problem. Therefore, it is necessary to classify the meter reading methods of electric energy meter.

1). IC card watt hour meter charging system

IC card meter charging system has the advantages of low cost, high reliability and long service life.

IC card uses silicon chip to store information. An IC card can also be used for at least 10 years. IC card electricity meter charging system has high security, is not easy to copy, charges accurately and is not easy to make mistakes. It has strong encryption. The use of IC card electricity meter charging system can improve the management level of residents' electricity charging and ensure that the power department can receive the electricity charge in time (if users do not continue to buy electricity, they will be cut off). The system functions of IC card meter include pre charging function, alarm function, power-off function, display function and encryption function.

The whole charging system of IC card meter includes three parts: host, IC card meter and IC card. IC card electricity meter charging system realizes the electronization of electricity charging. Its technology is mature and reliable. The power department can no longer worry about charging. However, from the perspective of the system, because the user terminal has no direct contact with the system host, the user can only know the user's situation when the user pays the fee with his card. The information feedback lags behind. It can be said that the user terminal is still disconnected from the whole network. In the long run, IC card charging system can only be used as a transitional product.

2). Remote automatic meter reading system

The remote automatic meter reading system realizes the automatic reading of power data, which can eliminate all the disadvantages of manual operation. The user's power consumption data can be directly entered into the computer management system of power business. The power consumption management personnel can monitor the power consumption at any time and deal with the problems (such as failure, power theft, etc.) in time. Using remote meter reading can obtain the total meter reading and sub meter total reading at the same time, grasp the line loss at any time, and easily analyze the cause of line loss for treatment. Residents open personal accounts in the bank, and the business computer management system is connected with the bank to complete a full set of operations such as automatic data copying, processing and bank transfer payment, which can truly realize the automation of power consumption management. At present, the remote meter reading system of Panjin power supply company adopts the low-voltage power line carrier meter reading system, which directly uses the existing low-voltage transmission line for data transmission. It eliminates the line laying project and has obvious advantages. The system is a high-tech product integrating microelectronic technology, communication technology and computer technology. It has the remarkable characteristics of high reliability and simple installation.

12. Functions and characteristics of charge control smart meter

Intelligent electric energy meter is composed of measurement unit, data processing unit, communication unit, etc. it has the functions of electric energy measurement, information storage and processing, real-time monitoring, automatic control, information interaction and so on. The circuit breaker is controlled by the output signal in the meter to realize the on and off of the load, so as to urge users to buy electricity first and then use electricity. Through a variety of rates to effectively adjust the load balance of the power grid, cut the peak and fill the valley, and make the use of electricity more reasonable and effective.

(1) Function

1. Electric energy measurement and multiple rate function: according to the preset time-sharing period, complete the time-sharing functions of each rate and total electric energy measurement of forward active power and reverse active power, each rate and total electric energy measurement of forward reactive power and reverse reactive power, and four quadrant reactive energy measurement.

2. Maximum electric energy demand recording function: record the maximum electric energy demand and its occurrence time, and select the demand cycle and slip time.

3. Electric energy freezing and storage function: freeze and save relevant electric energy data according to the specified time or real-time command every month. The frozen data includes forward active power rates and total electric energy, reverse active power rates and total electric energy, forward reactive power rates and total electric energy, reverse reactive power rates and total electric energy, and record the freezing time at that time.

4. Load curve recording function: record the rolling data of relevant parameter data according to the set time interval, and the interval time is set by the user.

5. Independent RS485 communication interface and infrared communication interface function: communicate under certain communication protocol through RS485 communication to realize local or remote meter reading and parameter setting.

6. It can measure the total and each split phase active power, reactive power, power factor, split phase voltage, split phase current, frequency and other operating parameters.

7. Electric energy meter data display function: set the contents of rotation display and key display according to the user's requirements, and display the corresponding power value on the display screen of the electric energy meter.

8. Event recording function: such as recording the times of voltage loss and current loss of each phase and the time of occurrence and end; Power down time, times, reset time, times, etc.

9. Zero clearing: it includes two functions: electricity meter zero clearing and demand zero clearing

10. Signal output, including electric energy pulse output and multifunctional signal output.

11. The clock adopts built-in hard clock.

12. The safety protection electric energy meter shall have dual protection measures of programming switch and programming password to prevent unauthorized person from programming operation.

13. Power failure meter reading in the state of power failure, it can wake up the meter to read data by pressing keys or non-contact.

14. The alarm shall be output by luminous or audible alarm. The alarm events include: loss of voltage, loss of current, reverse phase sequence, overload, battery undervoltage, etc.

(2) Characteristics

1. The power consumption of smart meters is low. Generally, the power consumption of each meter is only about 0.6W ~ 0.7W.

2. High precision. In terms of the error range of the meter, the measurement error of grade 2.0 electronic watt hour meter in the range of 5% ~ 400% calibration current is ± 2%, and the accuracy grade of grade 1.0 is widely used at present, with less error.

3. The overload and power frequency range is wide, and the overload multiple of smart meter can generally reach 6 ~ 8 times, with a wide range.

4. The State Grid Corporation of China has formulated strict specifications and standards in the form, specification, size, variety and communication protocol of smart meters, which is conducive to verification and installation.

13. Application of charge controlled intelligent watt hour meter in power grid

1. Optimize distributed energy allocation

There are still many problems in the grid connected operation of distributed energy and distribution network. Power supply enterprises use smart meters to monitor, control and adjust the distribution system in real time, master the characteristics of distributed power generation and its interaction with power grid operation, and optimize the configuration of distributed energy, so as to transmit electric energy to end users in the most economical and safe way of transmission and distribution, Improve the reliability and energy efficiency of power grid operation.

2. Improve the accuracy of load forecasting

With the popularization and application of smart meters, large users can upload their recent power consumption plan to the power supply company through smart meters. Users with distributed power supply can upload their power transmission plan and power generation data of distributed power supply through smart meters. Power supply enterprises take the capacity and time of users' planned power consumption and the sequence of users' planned power consumption as the accurate information of load forecasting, and automatically intervene in the load forecasting system, which can improve the accuracy of load forecasting, reduce the reserve capacity of power grid and improve the economic benefits of power grid.

3. Provide fault analysis basis

Power supply enterprises can monitor the power consumption of users in real time through smart meters, so as to realize on-line analysis, dynamic tracking and automatic control of abnormal states, and improve the reliability of power supply. When a fault occurs, the abnormal power consumption record can be queried through the intelligent meter to provide reliable real-time data for fault analysis.

4. Intelligent demand side management

Smart meters collect more real-time operation data of power grid (voltage, current and power, etc.), intelligently monitor and control the state and energy consumption of electrical equipment, so as to master more detailed user load, automatically prepare and optimize orderly power consumption scheme, automatic implementation, process tracking, automatic monitoring and effect evaluation, so as to achieve intelligent management on the demand side.

5. Promote the development of new technologies for intelligent power consumption

With the wide application of smart meters, power supply enterprises transform from manual meter reading to automatic meter reading, and obtain more power consumption data. After analysis and processing, taking the smart meter as the gateway, real-time electricity price information, payment information and power consumption information are notified to users through two-way real-time communication, so as to optimize customer service and promote users to make rational use of electric energy and participate in load regulation.

14. Conclusion and Prospect

At present, the contradiction between power supply and demand is prominent in the whole country, so is the unreasonable control of power consumption. Realizing power demand management and integrated power resource management is the direction of power supply development. Centralized intelligent electric energy meter can not only measure electric energy, but also realize electric energy control. When the power is sufficient, it can be measured at multiple rates to reduce the electricity price and encourage the use of electricity; When the power supply is tight, the power consumption can be limited or stopped, and the electricity price can be increased to ensure the key power demand. At present, China's urban communication network has been relatively complete and has been extended to all corners. It applies centralized intelligent electric energy to build an intelligent electric energy management system, and establishes an electric load control system through remote meter reading combined with communication network technology, so as to realize the balance of power supply and demand and ensure the safety of power grid. It has broad application prospects, and also provides a new way to realize power demand side management.

Intelligent meter reading system is a system that uses the perfect combination of contemporary microcomputer technology, digital communication technology and measurement technology, integrates energy consumption measurement, data acquisition and data processing, and combines urban residents' energy consumption information with comprehensive processing. The system enables the power supply department to fundamentally reduce the complicated labor of manual door-to-door meter reading. Accurate and convenient charging system can not only save manpower, but also reduce disputes between relevant business departments and customers. It can not only improve the work efficiency of management departments, but also meet the new needs of modern users for payment.

Note: for some users who report that smart meters are fast, this problem is due to the high calculation accuracy. For example, TV standby will also consume power. The accuracy problem of the old electromagnetic meter will not measure the standby loss. Now smart meters can measure accurately. Everyone has questions about the meter and can check it in relevant departments, Each watch is allowed to be installed only after being appraised by a professional department.