Effective application of remote meter reading technology in residential community

Abstract: for a long time, the manual method has been adopted in the electric energy data reading and calculation of power supply companies. With the development of power system, especially the deepening of measures such as one meter per household and direct supply to households, the volume of this I. work has increased greatly, the manual operation has been difficult to be completed quickly, and the man hour cost is large, The application of remote meter reading technology in residential communities is an inevitable trend of development.

1、 Review of the current automatic morning reading technology

At present, the developed remote meter reading system is a centralized remote meter reading system in a single distribution transformer community, and the networking topology is "user meter, unit data acquisition equipment, distribution transformer centralized equipment and business department host". Generally, there are l2-14 low-energy voltmeters in a unit in the residential community. The unit data acquisition equipment is responsible for the electric energy and electric quantity data acquisition of the unit. The distribution and transformation centralized equipment collects the data of each unit, and the host of the business department makes the final reading. The main methods of data transmission include two-level pure dedicated line networking, hybrid networking and carrier networking.

In terms of networking topology, special channels should be built between user tables, unit data acquisition equipment, distribution transformer centralized equipment and business department hosts. The construction investment and quantities are relatively large, and the maintenance is also a very cumbersome project. At present, major development and research institutions are trying to reduce the intermediate links of single metadata acquisition equipment, Carry out low-voltage power line carrier communication directly between user meter and distribution transformer centralized equipment, establish the networking topology of carrier watt hour meter, distribution transformer centralized equipment and business department host, and improve the meter reading efficiency.

2、 Pilot scheme of remote aging in some residential communities

In carrying out the pilot work of remote meter reading in some residential communities, the scheme design should follow three principles: · the existing low-voltage power line should be used for data transmission between community transformers and households; the second is to install data transmission and receiving equipment between distribution transformers and households with direct link, and there is no other forwarding equipment in the middle; the third is that the user meter has the function of measuring electricity at the same time Local protection and remote monitoring.

2.1 system composition

The whole system shall be composed of three nodes and one channel. The three nodes are the business department management system, the information centralized system of distribution transformer and the user terminal installed on the low-voltage power line. One channel is the communication channel, which is installed on the corresponding equipment respectively. The power management information is exchanged and transmitted in the upper and lower channels of the system, The medium of information transmission from the management system of the business department to the information centralized system of the distribution transformer is the spread spectrum wireless channel, and the medium of information transmission from the information centralized system of the distribution transformer to the user terminal is the low-voltage power line carrier channel. The whole system presents a tree radiation distribution and has a large expansion space. The main purpose of the system is to transmit and copy the power data of low-voltage users, and remotely monitor the power load and state.

2.2 network communication

Channel sharing is divided into controlled access and random access. The use of random access shared channel belongs to contention access mode. It is typically used as carrier sense multiple access / conflict detection (CSMA / CD) network. The structure is general linear, which is more suitable for spread spectrum carrier linear sweep signal (chirp) and more suitable for power line transmission characteristics, However, CSMA protocol network has some defects, such as uncertain delay and low efficiency when overloaded. Because the data transmission volume of remote meter reading system is very small, it can be ignored.

3、 Terminal design

The main components of user meter design are AC / DC switching power supply, electric quantity sensing device, fault protection, measurement and compliance control, low-voltage spread spectrum carrier communication and other modules. The terminal multi output switching power supply focuses on the main function of power supply, and the top2xk pulse width modulation power switch is used to form a single ended flyback circuit. In the fault protection mode, when the circuit fails, it transmits a request signal to the MCU system module to start the power-off control. The metering module mainly converts the user's electric power into pulse train and transmits it to MCU system module to count the power. The load control module mainly controls the load by means of zero shutdown and 6kW load power. MCU system is responsible for calculating power data and implementing remote monitoring. The display module is mainly used to display the power data. The low-voltage spread spectrum carrier module is composed of three parts: low-voltage power line spread spectrum carrier network controller, power line coupling circuit and pre power amplifier [4]. The design distance of data communication is 1000m, and not less than 600m in special cases.

4、 Design of distribution transformer concentrator

The distribution transformer concentrator is mainly composed of three phase separated coupling low-voltage spread spectrum communication modules (3), three phase configured watt hour meter modules (3), two port RAM (3), u single chip microcomputer system, industrial computer system and telephone line modem. The main starting point of configuring low-voltage spread spectrum carrier communication module in phase separation is to prevent cross phase coupling carrier signal. The starting point of configuring electric energy and MCU circuit in phase is to make the concentrator convenient for parallel processing of user terminal data of each phase and improve the efficiency of data transmission and processing.

5、 Design of business station reading master station

The host of the business station reading master station is composed of PC machine, telephone line modem and software, which is responsible for data transmission, analysis and disposal between the business station and the distribution transformer data acquisition system. The management host can also use the telephone line modem ~ u to connect with the electricity collection bank to build a convenient payment channel. The main functions of PC microcomputer are the concentration of power consumption data of user terminal, power transmission meter parameters, power consumption, arrears reminder and power failure control. At the same time, it is responsible for power consumption monitoring in violation of regulations, power consumption information query, report preparation and output and other functions. The combination of timing and irregularity can be used for power consumption information collection. A single user can check the power consumption at any time, send and transmit the power consumption to the terminal according to the address and phase, timely remind the user to pay the electricity charge on time, and transmit the illegal information to the electricity supervision Department to maintain the order of electricity consumption.

Adopting direct power supply to households is an effective marketing strategy implemented by power supply enterprises. Under this marketing mode, the business volume of power reading and calculation of power supply system increases rapidly, and the operating cost increases accordingly. The effective improvement of remote meter reading system in meter reading can improve and enhance the efficiency of power marketing and transform the user terminal design into intelligent terminal, On the basis of power recording, taking into account the functions of power theft protection, misconnection protection, fault protection and remote power shutdown and transmission, it can effectively improve the effectiveness of power consumption management of power supply enterprises.