OUT OF THE BOX: ARIS C303

It seems like it is an easy thing to develop a controller. Develop motherboard, modules of different functionality, firmware and configuration utility - and you are ready to take over the market!

But it is not that easy in reality. Lots of details await you on the road to the ready-to-use product which purpose is to perform specific monitoring and control functions in electric power systems.

To develop a product which has maximum set of functions and is capable of operating in harsh environments (wide temperature range, electromagnetic interferences, etc.) and which is at the same time is simple to use is quite a difficult job.

All the requirements have to be taken into account, precisely reflected in product technical specifications and thoroughly implemented by the development team.

Developers must thoroughly plan hardware and software product architecture. If support of proprietary communication protocols is in plans, revision control and software updates systems have to be implemented. And there are many more aspects to note which are not visible to a regular engineer.

As you may have already understood today we will be testing a bay controller. ARIS C303 intelligent electronic device (IED) has been provided by Prosoft Systems and we will check how they tackled with the problem of bay controller development. We will also take a thorough look at IEC 61850 implementation in this product.

Product design

First you judge "how nice", then you judge "how wise'. We will do the same. Once you get to know ARIS C303, you will never mix it up with any other product. It may only be possible if someone copies this IED. Angular 19" enclosure, black mat front panel, 5.7" high-resolution

display (capable of visualizing animated single-line diagrams), keyboard, switchgear control mode selection switch - this is all ARIS C303 (Figure 1).

Figure 1. Front panel control and indication elements.

Front panel also includes service interfaces and LED indication elements. Everything looks neat and clean. Introducing settings via integrated keyboard is an easy thing to do. IED has modular design and has 14 slots for installation of different types of modules. Access to these slots and their interface is available from the back.

Figure 2. View from the back.

Modules, modules, modules…

This device is a monster as it is supposed to be. Besides one or two power supply modules and one or two processor boards, ARIS C303 can be equipped with up to 14 modules of different functionality. The following modules are available:

CT/VT direct connection modules, implementing measurement and waveform recording functions.

IEC 61850-9-2LE modules, allowing to receive up to 4 Sampled Value streams, implementing measurements and waveform recording functions.

RS-485, RS-232 and Ethernet communication interfaces modules. 24 V (8 or 15-channel) or 220 V (7 or 1- channel) binary input modules. 220 V binary input modules with operation voltage setting and rejection functionality

(15-channel). 24 V (8-channel) or 220 V (8-channel) binary output modules. Analog current input modules (0…5 mA, 4…20 mA, 0…20 mA). Analog voltage input (0…1 V, 0…5 V, -10…+10 V, 0…10 V). Remote control modules with support of select before operate functionality (220 V).

ARIS C303 that has been tested was equipped with the following modules: two 220 V 15-channel binary input modules, two 220 V 8-channel binary output modules, 8-channel analog signal input module and measurements and waveform recording module with capability of direct connection to current and voltage transformers. IED also included the following basic modules: one power supply module and processing board with GPS/GLONASS receiver (Figure 2).

Processing board provides time synchronization functionality. There is an integrated GPS/GLONASS receiver inside and if you connect an antenna to it, IED will become time synchronized. Alternative solutions to provide time synchronization of the device: either time synchronization over NTP or by using Prosoft GPS Module external precision time source which is connected to RS-485 port of IED (communicating over TSIP protocol). ARIS C303 can also play a role of NTP-server.

ARIS C303 is capable of operating in harsh environmental conditions, withstanding electromagnetic interferences according to IEC 61850-3 and wide temperature range (from -40 to +55 °С). As we were assured every piece of equipment developed at Prosoft Systems is tested on electromagnetic immunity and safety. Primary calibration of devices is also performed in Prosoft Systems labs.

Functionality

With variety of modules ARIS C303 must provide rich functionality. And it does. Interlocking and user-defined algorithms (implemented using Function Block Diagram language), metering and waveform recording functions - all of them are available for use. 

Data transmission and reception is possible using variety of communication protocols: IEC 60870-5-101, -104, -103, Modbus (RTU/ASCII/TCP), SPA, START and set of proprietary communication protocols. 

IEC 61850 is also implemented and we will take a closer look at specifics of its implementation. 

IEC 61850 implementation 

First, we will take a look at information model (Figure 3). It's dynamic: it changes depending on the set of modules installed. The idea behind is as follows: each logical node corresponds to the specific module. Number of logical node data objects depends on the number of input/output channels of the module. User won't feel that it's dynamic from the very beginning - IED comes factory preconfigured. But once there's a need to change set of preinstalled modules, user sees that. To represent external function and equipment with status signals, GGIO logical nodes are used. Though we were assured that Prosoft-Systems engineers are working on data object implementation that preserves semantic, using a variety of standard logical nodes. Switchgear and measurement functions are represented by appropriate standard logical nodes (XCBR, XSWI, MMXU, etc). 

Figure 3. IED information model.

The following communication services are supported:

GOOSE publisher/subscriber. IEC 61850-9-2LE Sampled Value subscriberп (of up to 4 80 samples/cycle or 256

samples/cycle streams). Client-server functionality - IED can take roles of both client and server (supporting

buffered/unbuffered reporting).

As you can see, IED is capable of performing a variety of functions. How enhanced functionality influences configuration user interface usability? Let's check.

Configuration interface usability

Web-interface configuration utility is a very ambiguous solution which has both supporters and opponents. Supporters say that full configuration of an IED using a web-browser is not sensitive to operating system installed and that there is no need for additional software packages. Opponents say that it is not possible to configure several devices of the system simultaneously.

Putting aside subjective sentiments we will try to evaluate ARIS C303 configuration interface usability.

When IP-address of the specific IED is set in web-browser and authorization is a success, user sees quite accurate main page of ARIS C303 web-interface. It looks neat and clean.

Main menu has 7 menu items, which are located on top and are drop-down lists. These menu items are also available in tree view and may be visualized in such way when ‘Do you want to see the list of all available services?’ link is selected.

First of all, it is interesting for us to evaluate usability of IEC 61850 communications configuration procedure.

Configuration of GOOSE publishing and reporting is quite regular and intuitive. First, user has to create a dataset. For this it is required to right click on Datasets menu item and to choose Add dataset option. Required information model data objects/attributes are added to the dataset (Figure 4): to select specific data user navigates through information model tree and checks Add to dataset menu item for all required elements. It's quite convenient, but there is one thing that bothers you a little bit – you have to confirm selection of each and every data object/attribute by choosing Apply changes menu item. In most configuration utilities that we have been working with elements are added to the dataset using drag and drop action with single confirmation of dataset structure. The latter seems to be more convenient.

Figure 4. Creation of a dataset.

If it is required to configure IED to publish GOOSE messages, GOOSE control block must be created which is done in a quite similar way to creation of a dataset (Figure 5). Then user has to open control block structure and to set its parameters. Everything is easy and intuitive here. Specific dataset may be selected from the drop-down list. It’s nice that control block configuration procedure is accompanied by a tip regarding Destination MAC-address permissible range. It makes you understand and think about this parameter which is quite important when multicast filtering is implemented in substation LAN.

Figure 5. GOOSE control block configuration.

It's also easy to configure buffered (Figure 6) and unbuffered (Figure 7) report control blocks. But we have found several drawbacks.

For unbuffered report control block it’s not possible to set BufTm parameter. It seems like some misunderstanding slipped in here. This parameter doesn't have to do anything with buffering of reports but defines time interval over which all occurred events are included in the single report. BufTm parameter must be available for both buffered and unbuffered report control blocks.

We also noticed that naming of several optional fields that may be included in report is not correct: for example, instead of data-reference optional field control block reference field is available, though the latter is not there in the standard.

Figure 6. Buffered report control block configuration.

Figure 7. Unbuffered report control block configuration.

For buffered reporting it’s not possible to configure IED to send buffer-overflow optional field; both for buffered and unbuffered reporting there is no possibility to transfer configuration revision (conf-revision) optional field.

Data reception configuration procedure is straightforward. It’s required to set IP-address of the server in under Data reception menu item. Then user has to select Create menu item (Figure 8).

Figure 8. Reading server configuration data over MMS.

ARIS C303 will read server configuration over MMS and information model of the server will be available for overview under Device description menu item (Figure 9). There user can also generated CID file of the server based on the presented structure.

Figure 9. Visualization of server information model.

Then it will be possible to overview datasets (Figure 10), report (Figure 11) and GOOSE (Figure 12) control blocks available on server.

Figure 10. Server datasets.

Figure 11. Server report control blocks.

Figure 12. Server GOOSE control blocks.

To be able to receive data using one of the IEC 61850 communication services (either reporting or GOOSE messaging) it is required to choose either Reports (Figure 11) or GOOSE messages (Figure 12) menu item, check appropriate control block and choose Apply menu item.

For reporting it is required to set trigger options and to define optional fields which will be included in report along with the data (Figure 13).

Figure 13. Server report control block configuration.

For GOOSE messages user can create service data channels (Figure 14): this will activate calculation of missed messages, visualization of state number, sequence number, etc. This data will be available for use further.

Figure 14. GOOSE service data channels.

Data reception configuration is done in one click.

For configuration changes to come into force it is required to restart controller which takes some time. But you will not get bored – useful tips will be available on display screen (Figure 15). And they are really useful.

Figure 15. Tips available at restart.

Data reception configuration procedure has the same drawbacks as data transmission configuration procedure. For unbuffered reports it will not be possible to set BufTm parameter, because there is no such field. The same drawbacks are reside in optional fields settings.

In general configuration interface usability is at good level. It's thought-out.

Final thoughts

ARIS C303 is worthy representative of microprocessor-based devices, developed and produced in Russian Federation. It shows good results in all disciplines: design, ergonomics, functionality, and web-interface. All is good. Not every product can be characterized in such way. It’s obvious that great number of engineers has been working on the product. And this means that minor drawbacks will not last.