With the rapid development of the electric power industry, users are demanding more and more power supply quality and power supply reliability. The transformation of urban power grids must address the issues that need to be addressed to improve the automation technology and reliability of urban distribution networks. In the next few years, urban power grids should accelerate the construction of grid structures and the construction of urban distribution automation systems to improve power supply quality and power supply reliability to meet the power supply needs of modernization.
Because of the large scale, high investment, and complicated technology of a power distribution network system, a development-oriented, distributed, practical, efficient, stable, and reliable system can achieve its intended purpose. The communication system is the key technology for building the distribution automation system. The quality of the communication system determines the advantages and disadvantages of the automation system to a great extent. The distribution automation must use reliable communication means to deliver control commands from the control center to Each implementing agency or remote terminal uploads various information collected by remote monitoring units to the control center.
one. Distribution Network Communication Features and Requirements
At present, China's distribution network automation is mainly based on 10kV lines, including automation of 10kV feeder lines, automation of opening and closing stations and community distribution, automatic detection of distribution transformers and capacitor banks, etc.
The main problems of the current distribution automation system are: poor system stability and poor practicality; management and maintenance work are lagging; some system planning functions are large and impractical. In addition, an international common problem is the phenomenon of “islands of automationâ€, with poor information sharing and inconsistent data sources. It is recommended that such a large-scale system adopt top-down design, bottom-up development, overall planning, and strategies implemented in phases.
For the communication of distribution network automation, the characteristics and requirements should be clarified, and the system design and product selection should be more targeted.
1. Distribution Network Automation Communication Features
l Many nodes and many types of services
l Communication nodes are scattered
l Short communication distance (within a few kilometers)
l Poor environment (mostly outdoors, strong electromagnetic interference, high and low temperature, etc.)
2. Distribution Network Automation Requirements for Communication
l High stability and reliability of the communication system, and redundancy in transmission failures
l Flexible networking and strong scalability
l Bidirectional communication capability
l Good real-time performance and security
l Industrial quality (including wide temperature and humidity, electromagnetic compatibility, anti-vibration, redundant power supply, installation methods, etc.)
l Unified network management
two. Industrial Ethernet Solutions
We particularly recommend a Omate 6000 series industrial Ethernet switch certified by Kema, which meets the requirements of the market for distribution network automation communication. It is increasingly large, and the scale and communication of communication systems. The specifications and performance, flexibility, reliability, security, and convenience of installation and maintenance are mainly reflected in:
l High requirements for communication bandwidth and flexible networking. The development of more complex ring networks with optical branches, tangent ring networks, tree networks, and hybrid networks.
l The requirements for reliability and real-time performance of data transmission are higher. Reliability and real-time nature are just one of the objectives pursued by the distribution network system. With the expansion of the network scale, the higher the requirement for communication is. How to meet the goal: The average urban area is 99.96%, the average power outage time per household is no more than 3.5 hours; the central area of ​​important cities should reach 99.99%, and the average power outage per household is no more than 53 minutes, which is a historic mission before us and opportunity!
l The security requirements for data transmission are higher. The distribution network has high requirements on the network security of the communication system. Therefore, access control, data encryption, channel protection, network management response and fault location should be more comprehensive.
l Easy installation and maintenance. The larger the scale of the network, the higher the degree of system automation, and the higher the requirements for the installation, maintenance and management of the communication system. Including the equipment on-site installation is simple, flexible and diverse debugging methods, the humane network management system, the diversification of fault alarms.
The system architecture uses the GOE200 Gigabit Industrial Ethernet Switch to establish the backbone network between substations (the existing backbone Ethernet channel can also be used). The distribution substation is constructed by the Omate6000 self-healing ring network, and each ring network device It can be determined according to the actual amount used on site. The use of Omate6000 100M industrial Ethernet switches to form the ring network taking into account the reliability of data transmission, due to the unique Jiffy Ring instant ring network redundancy technology Omatic, fundamentally guarantee the reliability of data transmission.
From the terminal access, to the substation transmission, and finally the scheduling master station network, truly realize the "E" in the end, greatly simplifies the network composition, solves the problem of interconnection and interoperability, and truly achieves resource sharing.
Some of the video surveillance services sometimes required by substations can be accessed through the station's industrial Ethernet switches, and the video surveillance signals and control signals are isolated through different VLANs, plus the good QoS and port rates of OAM Industrial Ethernet switches. The control function can well ensure that the traffic of the main data is not affected by other services. For larger systems, it is recommended to completely separate the video surveillance system from the distribution network system.
Program advantages
1. Industrial quality, low power consumption fanless design, strong and flexible structure. For harsh industrial environments, such as high temperature, hot and humid, strong electromagnetic interference.
2. From the access and transmission to the final dispatch master network, the “E†is truly realized. This greatly simplifies the network configuration and solves the problems of interconnection and interworking.
3. Simple networking, high reliability, and high scalability, the system has simple, flexible expansion and intelligent upgrade capabilities, and facilitate the continuous expansion of the system.
4. Networking, through a dedicated communications network, synchronized, real-time management to view the site information distributed in various places.
5. The information resources in each field area can be fully shared with other management systems and can be coordinated and coordinated as required.
6. Omate 6000 good exchange performance and instantaneous self-healing ability, greatly ensure the reliable and timely transmission of data services. When the transmission network fails, the ring network service can be automatically recovered within 18ms.
7. Support RSTP, Trunk (802.3ad), dual power redundancy, fault self-diagnosis and other functions to improve the reliability of the equipment.
8. Clock Synchronization: SNTP, PTP (IEC1588) Network Clock Protocol
9. Network security: password protection, port enablement, VLAN isolation, 802.1x access control, SNMP V3, fault alarm, etc.
10. Rich management style: In addition to supporting standard SNMP v1/v2/v3, it also provides Web, Telnet, CLI, and Console, as well as further user-friendly RMON and OPC interfaces.
three. Conclusion
The design and selection of any kind of communication network requires consideration of the practicability, reliability, security, and scalability of the network in addition to the cost-effectiveness. Distribution network automation is still in the initial stage in our country. Only by continuously improving and improving our communication means using new technologies can we meet the need for continuous expansion of distribution automation.
Omar Industrial Ethernet data exchange products have the following superior features:
1. Good equipment characteristics & installation flexibility, wide temperature, dustproof, moisture-proof design: Operating temperature: -40 ~ 80 °C, storage temperature: -45 ~ 85 °C, working humidity: 5 ~ 95% (non-condensing ); metal enclosure without fan cooling technology, IP40 high level of protection; can be customized rack, rail, wall mounting;
2. Reliable and stable work in the harsh electromagnetic environment: Through industrial four-level electromagnetic compatibility testing, it has high protection performance in data port lightning protection, anti-fast bursts, anti-static and other aspects, which can effectively prevent industrial interference: high voltage AC Electric fields, electrostatic fields, arcs, thyristors, etc.; Defense against natural disturbances: lightning impacts, various electrostatic discharges, magnetic storms, etc.;
3, the average time between failures of the equipment exceeds 300,000 hours, spare parts are provided for many years;
4. Instant Ring Network Self-healing: Support Jiffy-RING ring network redundancy technology, improve the network security, reliability, stability, and ensure the network communication of bumpless switching, switching time is less than 18ms (network self-healing time) .
5, security advantages:
1) Support VLAN (virtual local area network) technology
VLAN is an essential function of the security switch. VLANs may span one or more switches, regardless of their physical location, as if the devices were communicating between the same network. VLAN can implement broadcast domain isolation on the switch. It can divide the network into a separate area and control whether these areas can communicate.
2) Traffic control (traffic control)
The traffic control of the switch can limit the abnormal load of the switch bandwidth due to the excessive traffic of broadcast packets, multicast data packets, and unicast packets with incorrect destination addresses, and can improve the overall system performance and maintain the safe and stable operation of the network.
In addition, the Ommet switch also provides bidirectional (in/out) separate limits for each port.
3) Supporting port aggregation, the aggregation function of multiple ports not only improves the link transmission bandwidth, but also provides redundancy protection for the link;
4) The QoS mechanism adopts the IEEE 802.p QoS CoS/TOS/DSCP priority strategy to ensure real-time reliable transmission of key data.
5) Supports broadcast storm suppression and IGMP-Snooping multicast protocols to improve network transmission efficiency
6) The log function of the switch can send information such as system errors, system configuration, status changes, and periodic status reports to the log server. The network administrator can use this information to know the operating status of the device, identify problems as soon as possible, and perform configuration settings and troubleshooting in a timely manner. To ensure the safe and stable operation of the network.
7) SNMP v1, v2, v3 (Simple Network Management Protocol) and RMON management are supported to facilitate unified management of third-party devices across the entire network.
8) Support the power supply to prevent reverse connection, as well as logging the power loss of the external field.