A year ago, Siemens Power Transmission and Distribution (PTD) commissioned a station automation system based on the IEC 61850 communications standard in Switzerland. Now PTD is working on its 100th project applying this standard, this time in China. In this case, the project is a transformer substation for the 500/220/35-kV voltage levels in Nanqiao, on the southwest outskirts of Shanghai, for which Siemens is replacing the complete station automation technology. The new Siemens automation system, used in conjunction with the communications standard, improves network operation, thereby increasing the reliability of Shanghai's power supply.

The transformer substation of the East China Power Grid Co. plays a key role in supplying the city of Shanghai with electricity. This is due to its position at the end of a high-voltage direct current transmission (HVDC) route via which electricity is transported more than 1000 km (600 miles) from Gezhouba in central China to Shanghai. This HVDC transmission system is the first of four large HVDC long-distance links Siemens has built or is currently installing in China.

To modernize the Nanqiao Substation, Siemens is deploying the Sicam PAS station automation system together with Siprotec-4 bay controllers. Thanks to the modular design and scalability of its hardware and software, Sicam PAS covers all the requirements of small industrial systems up to the high-voltage and ultrahigh-voltage levels. The integrated parameterization, test and diagnosis program simplifies startup and the analysis of malfunctions in secondary systems. Future expansions will enable short downtimes.

Data communication between the devices is via a redundant 100-Mbs Ethernet fiber-optic ring that complies with the IEC-61850 standard. This cuts equipment reaction times substantially and facilitates the setting of parameters. The project is one of the first in which Siemens employs bay controllers, operating with integrated and exchangeable IEC-61850 optical-fiber Ethernet switches with ring redundancy function. This configuration simplifies the wiring and offers the necessary operating reliability.

At present, the use of integrated switches in switchgear construction is unique to this project. An additional switchgear interlocking level is implemented directly in the process with the aid of so-called Goose (Generic Object Oriented Substation Event) messages, whereby prioritized telegrams are exchanged between the bay controllers.

As systems integrator, Siemens PTD is also combining the Sicam PAS automation system with an operator control and visualization system from a Chinese manufacturer via telecontrol protocol IEC 60870-5-104.