In the control, transmission and communication with PKUS SR24 registration system panel, the commands are divided into three groups: 1-8, 9-16 and 17-24. Each group is transmitted in its digital stream (in its own time slots). Moreover, for each group, two logical directions for receiving and transmitting TPE1 and TPE2 are provided, for which their digital streams are also allocated. Thus, it is possible to send and receive commands in six directions maximum.
An example is shown at the picture below. Here, the commands 1-7, 8 and 9-10 are transmitted and received in three directions: the commands 1-7 between the S1 and the S2, the command 8 between the S1 and the S3 and the commands 9-10 between the S1 and the S4.
In UMUX1500 multiplexer the time-slots from E1 stream transferred to the LOMIF module from PKUS SR24 are distributed in the SYNAC module to three VC12 containers that are transmitted via transport network to three Substations. Below is an example where the commands of each group are transmitted in the E1 stream at 64 kbit/sec. (one time-slot is used for each group). The using of a larger number of time-slots for each group will result in a shorter time for the RPA commands transmission.
The connection of the control, transmission and communication with PKUS SR24 registration system panel can be made directly to the multiplexers via the E1 electrical interface with a use of twisted pair. However, due to the presence of electromagnetic interference and the presence of potential between the installation locations of the multiplexer and PKUS SR24 at the Substation, it is recommended to use a fibre-optic cable (FOC) in case of short circuits on the transmission line.
To achieve that, converters of optical interfaces to electrical E1 are used, these are single-channel PKUS SR24 EO1 or four-channel PKUS SR24 EO2 (hereinafter PKUS SR24 EOx), which are installed in cabinets with multiplexing equipment or next to them. The type of the optical interfaces PKUS SR24 and PKUS SR24 EOx in this case is preferable to install programmatically as an optical E1 (linear code CMI, cycle format G.704).
There could be any type of FOC, both multimode 850 nm and single-mode 1310 nm or 1550 nm, because PKUS SR24 and PKUS SR24 EOx use SFP modules, which can be selected based on the type of FOC used.
If the reservation of channels in the transport network with a use of the main and backup routes is required, you need to use the TPE1* and TPE2* reservation mechanism built into the PKUS SR24, for which separate digital streams are used, and for S2, S3 and S4 to install PKUS SR24 EO2 converter in the multiplexing mode of two electrical interfaces E1 into one optical interface. In the transport network, the main and reserve E1 streams are organized.
The main and backup routes for the channel between the S1 and the S2 are shown at the picture below. For the channels between S1 and S3 and between S1 and S4, the main and backup routes are organized in a similar manner.
During the commands transmission in three directions with reservation of routes in the UMUX1500 multiplexer, the time-slots from the E1 stream transferred to the LOMIF module from PKUS are distributed in the SYNAC module to six VC12 containers, three of which form to the main routes in the transport network, and three to reserve ones. Below is an example where the commands of each group, both in the main and in the backup directions, are transmitted in the stream at 64 kbit/sec. (one time-slot is used for each group).
The disadvantage of such solutions is the incomplete workload of E1 streams transmitted from S1 to S2, S3 and S4.
The main advantage of the solution is elimination of UMUX1500 access multiplexers from the network on S2, S3 and S4, which allows:
· To reduce the cost of implementation of the solution connected with RPA commands transmission;
· To simplify the network topology, which increases the reliability of organized channels of RPA commands transmission, and to reduce the cost of its operation;
To reduce the probability of staff errors connected with the channels for RPA commands transmission, with reconfiguration of the network for any purpose (addition of telemechanic channels, telephone channels, etc.), because in the used E1 streams (VC12 containers), it is impossible to transfer any other information.