Problems Existing in the Practical Application of Optical Fiber Protection

(1) Construction process problems

Optical fiber protection is the main protection of ultra-high voltage lines, and the safety and reliability of the channel plays an important role in the safe and stable operation of the power system. Since optical cable transmission needs to go through connection links such as transfer terminal boxes, optical cable machines, cable layers and high-voltage lines, and the construction process of optical fibers is complex and requires high construction quality, if there are errors in construction and testing before the protection device is put into operation, It will lead to the malfunction of the protection device, which will affect the safe and stable operation of the entire network.

(2) The problem of channel duplication

When the optical fiber protection is used in the power grid of 220kV and above, according to the requirements of the dual principle of the main protection of the line of 220kV and above, the signal channel of the longitudinal protection is also required to be doubled. Since the high-frequency protection is coupled in different phases, it can meet the The requirement of dual channels, if two sets of optical fiber protection are used as the main protection of the line, the problem of dual channel has always limited the large-scale popularization and application of optical fiber protection.

(3) The division of optical fiber protection management interface

With the increasingly close connection between protection and communication, the management interface of relay protection and communication is increasingly difficult to distinguish. If this problem is not solved systematically, it will directly affect the reliable operation of optical fiber protection.

For the protection of independent fiber cores, the demarcation point between the communication profession and the management of the relay protection profession is on the optical fiber distribution frame in the communication room. The pigtail above the distribution frame including the protection device belongs to the professional maintenance of relay protection, which requires the relay protection professionals to have certain optical fiber verification and maintenance skills.

(4) The problem of optical fiber protection on the bypass route

The optical fiber protection of the line is inconvenient to operate when the bypass is used. Since the optical fiber joint cannot be unplugged and inserted, the attenuation test needs to be re-tested every time it is unplugged and inserted, and frequent unplugging and plugging can easily cause damage to the flexible joint, so it should not be used. The method of plugging and unplugging the joint realizes the switching of Fibre Channel.

There is no separate bypass protection in the power grid. When the bypass replaces the circuit, the AC circuit is switched, so there is no channel switching problem, but there is an independent bypass protection for the power grid. For the optical fiber blocking type and the allowable longitudinal protection, it can be temporarily used. The method of switching the secondary circuit, but the optical fiber differential current protection cannot be replaced. At present, it is solved by adding a set of optical fiber differential protection separately for bypass protection. Some manufacturers have been seeking to solve the problem of optical fiber protection switching, such as using optical switches to achieve fiber channel switching.