What are active networks and passive networks?

Active power network refers to the distribution network with high penetration rate of distributed power sources and bidirectional power flow. The so-called "high permeability" means that high permeability and short-circuit current have a substantial impact, which makes the traditional distribution network planning, design, protection control and operation management methods no longer effective. The concept of active network is proposed for the distribution network whose access capacity is strictly limited by grid-connected technology.

A passive network refers to a network composed only of passive components. In any case, the energy sent by the network to the outside is not greater than the stored energy. Passive devices are all linear devices. The network (circuit) composed of pure passive devices belongs to linear network (circuit).

The difference between the two is that:

In the active optical network (AON), ONU devices are connected in series in the optical fiber network, and the signal received by each ONU is the signal after optical-electrical-optical conversion by the superior ONU. In the passive optical network, ONU devices are connected in parallel to the optical fiber network through optical splitters, and the signals received by each ONU are directly sent down by OLT.

When the network needs to add branches, the active optical network system must add optical interface boards at the branch nodes to increase the direction of light, while the passive optical network system only needs to replace the optical splitter, and the optical splitter with more branches can increase the direction of light, so the expansion of the passive optical network system is more convenient and the investment cost is lower than that of the active optical network system. At the same time, the passive optical network system has a more reliable network security protection mechanism, including: (1) single-node protection. The equipment failure of one node in the network does not affect the work of other nodes, and it has the ability to resist the simultaneous failure of multiple nodes; (2) For the whole network protection, the same dual-plane protection mechanism can be used to provide circuit protection of channel protection box 1+ 1, and automatically switch optical planes, thus effectively ensuring the security of the network.