The gateways for the HVDC systems Long Island, New York and Sayreville, New Jersey (project Neptune RTS, USA) connect the HVDC Control System
to Supervisory Control and Data Acquisition (SCADA).
Communication between gateway and SCADA in Long Island is implemented with the protocol CDC Type I, in Sayreville with the protocol DNP 3.0.
Thereby the gateways behave as "slave".
The communication between gateway and the TDC Control System (Station or Pole Control System) runs over Ethernet, TCP/IP by means of Simatic TDC protocol.
Thereby the gateways behave as "master".
That communication at Long Island between gateway and TDC Control System is redundant, wherein the lines are connected by Channel Switches (CS).
Control is done automatically via ipConv.
For gateways in redundant operation, maximum uptime is ensured with the "hot-standby" method. This means only one of the two devices is active at any time.
The passive device monitors the active one and if the active one fails, the passive one automatically steps in and resumes communication.
As RS232 interfaces only allow asynchronous data traffic, a Telecontrol Transformer (TCT) is used to interconnect different protocols
(e.g. bit synchronous or pulse length modulated protocols). The Telecontrol Transformer can be used for baud rates of 300, 600, 1,200 and 2,400 baud.
Our industrial PC IPC191V2 19" 1U is installed as hardware platform, that enables the transmission of up to 6,000 data points (information).
Remote administration of both HVDC systems is possible e.g. via modem, RS232 or Ethernet with ISDN router.
Neptune RTS, USA
A timestamp, if applicable and supported by protocol, can be transmitted.
At the end of June 2007, well ahead of schedule, Siemens Power Transmission and Distribution (PTD) successfully commissioned a new high-voltage direct-current (HVDC)
transmission link between Sayreville, New Jersey, and Long Island, New York. The HVDC system carries 660 MW at a DC voltage of 500 kV.
In July 2005, Siemens was awarded the contract to build the interconnection by Neptune Regional Transmission System LLC (RTS), Fairfield, Connecticut.
Thanks to this HVDC submarine cable interconnection, Long Island will receive power from the grid of New Jersey in a low-loss and environmentally compatible way,
which will help to cover a constantly growing power demand and strengthen the "backbone" of Long Island’s transmission system.
(Extract from the Siemens trade press information, Erlangen, July 2, 2007)