Integrating the auxiliary power consumption into the power station automation system in accordance with IEC 61850

The application

Fossil-fuel power station  

Integrating the switchgear into the automation system in accordance with IEC 61850

Modern power station automation systems enable the auxiliary power consumption switchgear in a power station to be integrated into the main automation system in accordance with IEC 61850. This not only eliminates the need for a separate switchgear automation system, but also saves engineering outlay.

In the past, the switchgear was connected in accordance with IEC 60870-101 or -104, depending on the protection technology. With the introduction of digital protection technology, it is now possible to transmit an event and the time at which it occurred to the main automation system via communication in accordance with IEC 61850, and to use this information for error analysis that is accurate to the millisecond. This is necessary in particular for medium-voltage process engineering outputs such as coal pulverizing mills and compressors.

 

Fossil-fuel power station  

Fossil-fuel power station

Low-voltage switchgear

Whereas in medium-voltage switchgear, the bus connection in accordance with IEC 61850 is almost completely established via state-of-the-art protective and control devices, low-voltage switchgear presents a challenge: open low-voltage circuit breakers now come with integrated protection and trip electronics, meaning that modular and new concepts are necessary here.

Typical layout of block systems with two busbars and switchover equipment  

Typical layout of block systems with two busbars and switchover equipment

In order to create a complete solution, it is essential that the switchover equipment for controlling the busbars is integrated. This means that, in the event of an error (undervoltage or transformer failure), consistent communication in accordance with IEC 61850 through to the main automation system is possible. To avoid expensive and cost-intensive gateway solutions, the logic and I/O components must be able to establish communication in accordance with IEC 61850 directly from the device.

This is the only way to use the fast cross-communication as a GOOSE (Generic Object Orientated Substation Event) in accordance with IEC 61850 to create interlocks. This reduces wiring effort considerably.

Integration of IEC 61850 communication into the low-voltage main distributors  

Integration of IEC 61850 communication into the low-voltage main distributors

Renovating the automation system

As part of modernizing the automation system in existing power stations, central marshalling concepts for integrating the low-voltage switchgear in accordance with IEC 61850 can prove to be economically beneficial. Phoenix Contact provides complete cabinet solutions for replacing existing marshaling levels with IEC 61850 communication.

The solution

Axioline I/O system

Axioline I/O system

Phoenix Contact provides the modular, extendable Axioline I/O system for just such applications. It is characterized by its vast range of options for signal processing. With Axioline, digital and analog data such as circuit breaker contacts and measured values are extremely easy to record and, using the new bus coupler, integrate into the main automation system in accordance with IEC 61850. Thanks to high-performance relay outputs, the circuit breakers can be controlled directly from the I/O system.

Interlocks can be created through the complete, standardized implementation of GOOSE communication. The signal and control voltage of 220 V DC ─ typical for a power station ─ can be connected directly to the I/O system without the need for an additional coupling level. In order to achieve short wiring paths, the bus couplers can be installed within the so-called control niches of the supply fields of a
low-voltage main distribution board.

Central IEC 61850 marshaling cabinet  

Central IEC 61850 marshaling cabinet

The switchover equipment is installed in the respective coupling field of the switchgear. All auxiliary contacts of the circuit breakers can therefore be recorded via the I/O stations across the shortest possible distance. As the current and voltage values of the supplies are often only considered as a single-phase measurement from the point of view of the auxiliary power consumption of the main automation system, the analog 4 to 20 mA signal can be processed by the measuring device. The corresponding floating contacts of the undervoltage relay for voltages of 70% and 98.5% of the nominal voltage are recorded as digital contacts in order to activate the switching logic.

One switch per switchgear forms the network from the I/O stations of the switchgear and connects this with the remote automation system control cabinets via the higher-level backbone with FO technology. Thanks to the use of the PRP (Parallel Redundancy Protocol) redundancy modules from Phoenix Contact, data communication without switch-over times is possible in a redundancy scenario, resulting in maximum availability when transmitting information to the main automation system in accordance with IEC 62439-3.

The advantages at a glance

  • Complete system solution from a single source
  • GOOSE communication in accordance with IEC 61850 for creating interlocks
  • Optimum error analysis thanks to an event-based time stamp
  • Freely adaptable switchover automation thanks to IEC 61131 programming
  • Direct connection of 220 V DC signals and control commands

Axioline in power stations

  • PROFIsafe modules for the safe switching of motors and valves, e.g . in the boiler protection area or near to the emergency trip wire controller
  • PROFIBUS bus coupler for connecting field signals to the main automation system
  • Bus coupler for IEC 61850 for connecting the auxiliary power consumption systems to the main automation system
  • Temperature modules, e.g . for recording the temperature of the pipe walls

PHOENIX CONTACT
SEA Pte. Ltd.

105 Eunos Avenue 3
#04-00
Singapore 409836
+65 6228 4900