EPON Solutions to Electric Power Distribution Automation Systems in Smart Grid（4）
Powerfuland flexible network construction mode: Its topology adopts the hand-in-handsafety rotation mechanism, secure and reliable. The link between station andelectric power distribution terminal has the “1+1” protection function and aprotective shift of less than 50ms, so the electric power distribution networkcan run reliably. Moreover, other topologies, such as tree,hand-in-hand link and ring, can be applied according to different actualnetwork structures.
Thehand-in-hand protection switching mechanism mainly adopts the above-mentionedmodel: OLTO and OLTI can either be two independent OLT devices or two PONboards of the modularized OLT devices. The active PON interface and the passivePON interface are in working state, the service information is synchronouslybacked up, and during the protection switching process the passive PONinterface remains the service features of ONU.Both OLT and ONUhave the link-state detecting mechanism, so protection switching can berealized through the auto or forced mode and automatic recovery can beconducted after the protection switching fault is removed.
PON transmission network: The optical fiber is used as the transmissionmedia and there is no source in the whole transmission, so it runs stably andreliably. The bidirectional high-bandwidth services can berealized on a single fiber with a downlink/uplink rate of 1.25Gbps.
QoS guarantees for multi-services: The QoS mechanism, based on ITU-TY.1291, is supported, including priority labeling, queue schedule, flowshaping, congestion limit and cache management. Different users and serviceshave different delays, jitters, guaranteed bandwidths and maximum bandwidths,and the DBA mechanism is supported so that the uplink bandwidth of each ONU canbe distributed and limited.
Advanced systemarchitecture: The whole series of products is based on the modularized design,supports multiple access modes and various bandwidths, guarantees smoothnetwork expansion and upgrade; its modularized structure of the power supplycan provide various power supply modes according to clients' requirements, suchas DC12V/DC24/DC-48/AC220V power supply.
VariousEthernet functions: Multiple technologies are supported, such as VLANisolation, port protection, MAC binding, IP binding, port limit, queue and flowcontrol, so the combination of multiple services can be developed withouttechnical bottleneck and upgraded smoothly.
Unified andversatile network management system: The network management system is serviceoriented and it provides the unified network transmission and networkingprotocol, address management, domain management, security management, useraccess management and so on. It has rich OAM functions such as configuration,alarm, performance monitoring, trouble isolation and security management. Atthe same time, it supports the CLI/GUI management, which is easy to use.
Industrial-leveldesign suitable to the electric power industry: ONU has two PON uplinks andprovides interfaces for services like GEPON, FE and RS232/485.It is suitable todifferent harsh environments for they can run in the temperature from -40℃ to 85℃, preventthunderbolt and powerful electromagnetic interference and comply with therequirements of IEC61850 electromagnetic compatibility.