Energy and Smart Grid

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Object management is carried out from dispatch center of the compressor station. Considering the fact that an object can be situated 150200 km far from the GCS, the task of organizing data transmission channel is not easy. In addition, between the dispatcher, that is at the GCS, and the operator, that is at the GDS, it is necessary to organize additionally voice communications. Copper four-wire cables have been mainly used to ensure dispatching voice communications up to the last few years. When it was necessary to transmit data to technological objects, special adapters were installed in order to transmit data at a speed of up to 2.4 kbps.

The speed is relatively small, but it’s sufficient to solve main tasks. The problem is actually how to divide one cable between voice communication and data transmission, which is performed in on-line mode, that is, not occasionally, but constantly? There are several options to solve this problem:

to install a sealing equipment on the cable;
to install one more cable;
to use radio channel additionally.

Due to the rapid development of power industry automation systems and digital broadband networks of trunk lines, the requirements for modern HF communication systems have changed.

New requirements for HF systems have been formed as a result of the use of digital technologies in high-voltage networks.

Currently, data and voice are transmitted over fast digital channels, signals and data of protection systems are transmitted simultaneously over high-frequency lines and digital channels (FOCL), forming a reliable redundancy.

The use of FOCL is not economically feasible for network branches and long sections of power lines. Here HF technology offers an economical alternative for the transmission of voice, data and signals-commands of Relay Protection and Emergency Automation.

Nowadays HF network branches are viewed as a system that reliably transmits protection data and provides a transparent, user-friendly interface for data and voice from broadband digital networks to the end user at a much higher bandwidth than conventional analog systems. From a modern point of view, high bandwidth can only be achieved by extension of frequency band. What was impossible in the past due to the lack of free frequencies is now being realized thanks to the widespread use of optical lines. Therefore, HF systems are intensely used only on network branches. There are also options when separate sections of networks are interconnected with FOCL, which allows to use the same operating frequencies much more often than when HF communication systems are integrated.

In modern digital HF systems, the information density using fast signal processors and digital modulation methods can be increased compared to analog systems from 0.3 to 8 bps/Hz. Thus, a speed of 64 kbit/s can run to a frequency band of 8 kHz in each direction (receive and transmit).

In 2011 FlexCom AG introduced a new digital high-frequency communication equipment “LightCom”, confirming its leading position in this field. LightCom hardware. When designing “LightCom” FlexCom AG has created a multi-service platform suitable for both analog and digital applications.

HF communication technology now, as before, plays an important role in the field of data transmission of protection systems. Trunk and high-voltage lines with voltages above 330 kV usually use dual protection systems with different measurement methods (for example, differential protection and distance protection). Various transmission methods are used for protection system data transmission to provide complete redundancy, including communication channels. Typical communication channels in this case are a combination of digital channels via optical lines for differential protection data and analog HF channels used to transmit distance protection command signals. HF technology is the most reliable channel for protection signal transmission. HF communication is a more reliable data transmission channel than others, even optical lines can’t provide such quality for such a long time period. HF communication often becomes the only channel for protection system data transmission outside the trunk lines and at the network terminations.