How are IEC 61850 Information Models related to Functions?

The common understanding of information is crucial for the understanding of the related functions that produce, consume, and exchange the information. Information is always "bound" to functions ... no function - no information.

Let's have a look at this function: 

Supervision of a temperature value ... report an alarm to a well known entity when the temperature change rate reaches a value of xyz ... this is the FUNCTION. Now we model it with IEC 61850:

The temperature supervision is modeled in the logical node MySTMP1. We use the data objects Tmp (reported every x minutes), RteAlm (reported when the value of the RteAlmSet is reached, e.g., 0.5 K/s).

This "function" is described in an SCL document ... here the MySTMP1 is bound to a topology (SSD), e.g., room temperature in building so-and-so, the reports are sent to the SCADA system mySCADA-client, ... the factory acceptance test can more or less be automated based on the SCL document.

The IEC 61850 STMP logical node model follows the temperature supervision function!! 

The function was there well before IEC 61850 was born!

IEC 61850 standardizes the information shared with a real function.

The following diagram shows the basic modelling approach in IEC 61850:

• IEC 61850-7-2 defines the foundation
• IEC 61850-7-3 defines the common data classes: MV for measurements, SPS for single point status, and ASG for analogue sessings.
• IEC 61850-7-4 defines the logical node and data object classes.

More details will follow ... stay tuned.

The real challenge with IEC 61850 is: You likely get the feeling when you start reading hundreds of pages: unable to see the wood for the trees.

Let me know if you need help ... after 30 years I can support you.

Pt 100 Temperature Relay with IEC 61850 GOOSE

Ziehl (Schwäbisch Hall, Germany) has integrated IEC 61850 GOOSE into their Pt 100 temperature relay for up to 12 sensors with electric 10 MBit/s Ethernet interface.

The TR1200IP can be used wherever multiple Pt 100 sensors (up to 12) need to be evaluated simultaneously:
- Motors or generators,
- also with simultaneous monitoring of bearings or, e.g., exhaust temperatures
- Transformers, also with additional core-temperature monitoring
- Machines and plants
Type TR1200IP temperature relays register the temperature of up to 12 sensors simultaneously and provide the values to the electric 10 MBit/s Ethernet interface.
2 IP protocols are supported, so the registered temperatures can be subsequently evaluated by connected devices that are linked with the TR1200IP via an Ethernet network. In motors, that could be a motor contactor, in transformers a transformer contactor with integrated overload function and thermal monitoring.
An alarm relay reports devices and sensor errors. Sensor breaks or sensor short-circuits are also transmitted via the protocol to the connected evaluation unit.

Click HERE for a general overview.
Click HERE for GOOSE configuration.
Click HERE for the manual.

The GOOSE messages could be received by an HMS SG Gateway either as a client or a server. The SG Gateway could convert the received GOOSE messages into an IEC 61850 server to provide Reporting and Logging and convert to IEC 60870-5-104 or DNP3.

Optical Fibre for Temperature Measurement in Power Systems

Optical fibres are known to be used in power systems because they withstand the rough conditions in high voltage environments – as such they are used in Substations for carrying messages, e.g., according to IEC 61850.

There is another very interesting use case of optical fibres in power systems: in generation, transport, distribution, and loads. One of the crucial measurements that can be applied to more efficiently use of electric power is measuring temperatures. But you may state that installing a lot of temperature sensors could be quite expensive!

With the application of optical fibre for measuring temperatures it seems to be a very promising approach to reduce the amount of power needed for many critical process like in huge data centers, high voltage lines and cables, transformers, switch gears, to name a few.

According to alquist (a UK based company specializing on measurement systems using fibres) there are many advantages of fibre as a temperature sensor:

• Simultaneously measures temperature and position over long distances
• Low cost – the sensor is made from standard 50/125 optical fibre zip cord - very cost effective
• Immune to shock/vibration and electromagnetic interference
• No electronics, wireless, batteries or moving parts in monitoring zone. Totally passive, minimal maintenance.
• Inherent high reliability (fibre has a design life of 30+ years)
• High temperature range -200°c to +500°c
• Extremely small for access in legacy areas with restricted space
• Easily installed in without any downtime or interruption of service

There are an incredible number of applications for fibre optics beyond their use as a simple communications links.

Download a very useful presentation given by Andrew Jones (alquist) [pdf, 2.8 MB]

The availability of myriads of “measurement signals” from various processes allows to more efficiently use energy, i.e., to reduce the amount of energy we need to consume to service our needs for modern life.

What ever will be measured in energy supply systems could be modeled and communicated with IEC 61850 – The Communication Standard for power system automation. One crucial focus of IEC 61850 is on measurements!

Wireless Temperature Sensors for Switchgears and IEC 61850

Monitoring the temperature of likely failure points within electric power switchgear provides invaluable data on the health of that piece of equipment. Wireless solutions for temperature monitoring of medium-voltage and high-voltage switchgear are appropriate means to get critical information about the health of switchgears – especially for aging switchgears that have an ever more crucial impact on the reliability of the electric power system.

Ruggedized passive wireless radio-based temperature sensor and monitoring systems are a great answer for medium-voltage and high-voltage electric power switchgear. The access to the these measured temperature values through IEC 61850 is now available by Intellisaw.

Access the Intellisaw website to read the benefits of their Wireless sensors.

Check the temperature measurement model STMP of IEC 61850.