WO2010101522A1

WO2010101522A1 - Method for detecting errors in an electrical power substation network

Info

Publication number: WO2010101522A1
Application number: PCT/SE2010/050245
Authority: WO
Inventors: Andrea Bonetti
Original assignee: Megger Sweden Ab
Priority date: 2009-03-03
Filing date: 2010-03-03
Publication date: 2010-09-10

Abstract

A method of detecting errors in a network is provided, wherein a vectorial space is defined based on attributes of the Generic Object Oriented Substation Event messages according to the IEC 61850 Standard. A device (10) for converting GOOSE messages according to the IEC 61850 Standard is also provided, the device comprising a network port (12) adapted to be connected to a digital network, at least one binary port (14; 16), and a memory comprising software (18) adapted to provide conversion between a binary signal on the at least one binary port and a Generic Object Oriented Substation Event (GOOSE) message on the network port. The conversion time is small enough to allow the device to interface conventional relay test sets for testing IEC 61850 protection relays. The device acts as IEC 61850 Substation Network Secure Access Point allowing the analysis of the GOOSE traffic with any tool without connecting any PC to the substation bus.

Description

Method for detecting errors in an electrical power substation network.

TECHNIC ALHEID

[0001] The present invention relates to a device for rapidly converting electrical power substation protection and control network messages (IBC 61850 GOOSE messages: Generic Object Oriented Substation Eve nts)in a substation local area network into electrical signal for interfacing with conventional relay test sets allowing to test IBC 61850 relays with a conventional relay test set

BACKGBOUND AKT

[0002] IBC 61850 is a standard for the design of electrical substation automation. IBC61850 is a part of the International Hectro technical Commission's (IBC) Technical Committee 57 reference architecture for electric power systems. The abstract data models defined in IBC61850 can be mapped to a number of protocols. One of the Current mappings in the standard is GOOSE (Generic Object Oriented Substation Event). This protocol can run over TCF IP networks and/ or substation LANs using high speed switched Ethernet to obtain the necessary response times of < 4ms for relay protection applications.

[0003] So far, for IBC 61850 relay testing applications, the IBC 61850 interface has been implemented as a software and hardware function embedded in the relay test set equipment that are equipped with an Ethernet port able to interact with GO O SE messages.

[0004] A partof the interface, the so called GOOSEmessage sniffing (or GOOSE network capturing), has so far been implemented in a PC, and the GOOSE messages are detected by connecting the PC Ethemetportto the IBC 61850 substation bus (LAN network). [0005] The embedded IBC 61850 interface in the relay test set is of use for relay protection engineers, who need to test protection functions by using for instance the TRIP GO O SE message as feedback of correct relay operation

[0006] Upgrading a non IBC 61850 relay test set, i.e., a conventional relay test set, into an IBC 61850 relay test set is an action that requires efforts from the technical and economical point of view. Very often the upgrade cannot technically be done and the mostcommon solution is to acquire a completely new test set with IBC 61850 interface. This is an expensive solution, considering the amount of relay test sets already available and correctly working on the market

[0007] The GOOSEmessages in a substation represent not only protection signals. The majority of them are control/ interlocking signals, and they do not require the use of a relay test set for the testing. Moreover, control engineers do not have the competence for using a relay test set, and as consequence of all this, the control engineers do nothave today an easy to use 61850 GO O SE test equipment to carry out their own tests with GOOSE communication

[0008] Eurthermore, the sniffing from the PC Ethernet port is potentially a dangerous action from the IT security point of view, as a traditional PC is supposed to be connected to the substation Ethernet bus.

[0009] While this sniffing from the PC Ethernet port can be carried out during the commissioning phase of the substation, it will hardly be accepted by the substation owner during the maintenance phase, as the PC might contain software that sends random GO O SE messages on the bus interfering with the normal operation of the substation, or it might simply send a high stream of broadcast Ethernet messages that can overload the substation bus creating communication problems among the different 61850 protection and control equipments (IEDs). [0010] Thus, it would be advantageous if the above mentioned drawbacks with GOOSE could be eliminated or at least reduced.

SUMMAKT O F IN VENΗO N

[0011] An object of the present invention is to provide a device and a method for avoiding or at least reducing the above mentioned drawbacks.

[0012] The invention is based on the realization that software programmed for conversion between a binary signal on at least one binary port and a Generic Object Oriented Substation Event message, in the following "GO O SE message", on a network port can be provided in a device.

[0013] In one aspect, the invention provides a method of detecting errors in GOOSE messages available in an electrical power substation network, comprising the steps of defining a vectorial space based on attributes of the GOOSE messages according to the IEC 61850 Standard, reading a first GO O SE message from the substation network, reading the same GO O SE message from the IEC 61850 engineering file (SCLfUe), and defining a distance between the scanned (or sniffed) GOSOEmessage and its partner on the SCLfUe, using the defined vectorial space. I^" the distance is zero, the two GOOSE messages are the same, and the message available on the network is exactly as designed on the SCLfile. If the distance is small, it can be said that the message on the network is possibly the same message on the SCLfile but with some differences that may cause other IEDs not to recognize it as a valid message.

[0014] According to a second aspect of the invention, there is provided device for converting Generic Object Oriented Sub station Event (GO O SE) messages according to the IEC 61850 Standard, the device comprising a network port adapted to be connected to a digital network, at least one binary port, and a memory comprising software adapted to provide conversion between a binary signal on the atleastone binary port and a GOOSE message on the network port

[0015] The invention allows analyzing the GOOSE messages for electrical power sub station network trouble shoo ting with combination of SCLengineering files and messages detected on the network and can be used as Secure Substation Network Access R)intfor observation of GO O SE message traffic without any need of setting and/ or testing.

[0016] The typical conversion time is of the order of magnitude of 0.5 ms and anyway always below 1 ms in order to not add a noticeable delay in the reported relay response time (operate time) by the conventional relay the test set that uses the converted electrical signal by the invention instead of the digital GO O SE message as feedback of the relay operation.

[0017] Thus, there is provided a device that can be interfaced with any conventional relay test set of any manufacturer for IEC 61850 relay testing.

[0018] The device according to the invention can be interfaced with any conventional relay test set from any manufacturer, because it translates the Ethernet GO O SE message into an electrical contact that activates a binary input of the relay test set

[0019] The invention provides a device in the form of a test instrument that control engineers will have a benefit in its usage. It does not require any relay test equipment competence in order to be used and does notneed to be connected to any relay test set for its use in substation control applications.

[0020] The device according to the invention solves the security problem as no PC is required to be connected to the substation Ethernet bus in order to be run. [0021] The device according to the invention is preferably equipped with two physically separated Ethernet ports. The first port (IEC 61850 port) is connected to the substation bus. The firmware in the invention transparently forwards the GOOSE messages detected atthe IEC 61850 portto the second Ethernet port (PC Port). A PC connected to the PC Ethernet port of the device will be able to show the GOOSE messages by using any third party application like GOOSE sniffers or IEC 61850 network analyzers.

[0022] An IPmessage erroneously sentby the Ethernet port of the PC will by no means reach the substation bus because there is nothing in the invention's firmware thatpasses any signal from the PC Ethemetportto the IEC 61850 Ethemetport

[0023] This means that the PC can see what happens on the substation bus but it cannot interfere with it The invention therefore acts as a Secure Substation Network Access Point

[0024] This behavior of the device according to the invention needs no testing in the substation because it is partof the design of the invention, and there is no setting in the invention that can modify or alter this behavior.

[0025] In a preferred embodiment, the software is implemented as firmware, whereby the risk of manipulation and corresponding security drawbacks is minimized. M this context, firmware is a term that is used to denote the fixed, usually rather small, programs that internally control various electronic devices, such as an apparatus according to the invention. This includes, but is not limited to, programmable contentof a hardware device, not only machine code for a microprocessor, but also configurations and data for application-specific integrated circuits, programmable logic devices, etc. Although modem devices thatcan be updated with new firmware typically employ semi-automatic methods, sometimes a storage medium, such as a socketed RDM, mustbe replaced. [0026] Further preferred embodiments are defined in the dependent claims.

BREFDESCRIPΠON OF DRAW INGS

[0027] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

[0028] Hg. 1 is a diagram showing the basic configuration of a device according to the invention (conversion of GO O SE messages in electrical signals in a typical conversion time close to 0,5 ms),

[0029] FIg. 2 illustrates the device of Fig. 1 interconnected between a conventional relay test set and a local area network,

[0030] Fig. 3 is an overview of a relay test environment comprising a device according to the invention, an IFJC 61850 relay and a conventional relay test set

[0031] Fig. 4 illustrates the device of Fig. 1 with the on board status indicators for all input and output devices,

[0032] Fig. 5 illustrates a device according to the invention provided in a power substation network as a Secure Substation Network Access R) int, and

[0033] Figs. 6a and 6b illustrate GOOSEmessages used for error detection.

DFSCF3PIION OFFMBODIMFNTS

[0034] In the following, a detailed description of preferred embodiments of a device and a method according to the invention will be given.

[0035] In the following description and claims, the term high power is used. It is to be understood that this term is intended to cover voltages of at least 400 volts or atleast lO kilovolts and up to 1 Megavolts. IEC 61850 Ffelay Testing with conventional relay test set

[0036] In a first application embodiment of the invention, described in the following with reference to Figs. 1-3, a general purpose IBC 61850 GOOSE messages converter is provided for use with a conventional relay test set to test IBC 61850 relays. Thus, a device according to the invention, generally designated 10, comprises a network port 12, such as an Ethernet port, adapted to be connected to a local area network (IAN), such as a power substation IAN.

[0037] Atleastone binary input 14 is provided and this binary input is adapted to be connected to a source of binary input signals, such as a relay test set 20 used for testing and simulating power equipment, such as a circuit breaker position or the like. When the relay test set20 wants to send a protection GOOSEmessage, itjust activates its binary output BO. . The test set binary output is connected to binary input 14 of the device 10, which is programmed to convert this electrical signal into a GOOSEmessage, which will be received by a protection relay connected to the power substation IAN comprising a network switch 30

[0038] Atleastone binary output 16 is also provided on the device 10 and this output is adapted to provide binary output signals, for example to the above mentioned relay test set 20. The binary output of the device 10 can thus be wired or in other ways be connected to binary inputs of a test set - any conventional test set has binary inputs to detect the relay trip from relay trip contact - and the relay test setperform the relay test against the IBC 61850 relay in the same it performed against conventional relays because the protection GOOSE messages are converted into electrical signals from the device 10.

[0039] The device 10 is thus adapted to convert GO O SE messages received on the network port 12 into one or more binary output signals which are provided on the at least one binary output 16. likewise, binary input signals received on the at leastone binary input 14 is converted into GO O SE messages, which are ouφuton the network port 12.

[0040] This conversion is performed under software, preferably in the form of firmware 18 provided in a memory of the device 10.

[0041] The device 10 is designed in such a way thatthe time needed to convert an Ethernet GO O SE message into electrical signal is small enough to allow the relay engineer to simply neglect it when he performs the relay operate time tests. Tb this end, the response time for converting GOOSE messages into electrical signals and vice-versa is typically of the order of magnitude of 0.5 ms, and always below 1 ms, which is short enough for not adding any additional time delay in protection relay testing.

Control Application

[0042] R>r Control Engineers itis important that the device 10 will notneed to be connected to any relay test set It will justbe connected to some auxiliary relay simulating circuit breaker position, or they will simply use the reporting feature (IED indication) installed in the device 10 to verify the correct value of the GOOSE messages on the network.

[0043] Today the procedure of sending GOOSEmessages on a IAN is complicated and requires a particular use of the relay test set that often is not designed for this particular application Thus, control engineers often have the need to send GOOSEmessages upon activation of a simple button

[0044] In order to provide this functionality, the device 10 is provided with one or more binary inputs, such as ten binary inputs. These binary inputs are adapted to be connected to a respective electrical switch and the firmware 18 provided in the device 10 is programmed to activate GOOSEmessages on the network in response to the closing of these switches. Correspondingly, one or more binary outputs may be provided for outputting binary information.

[0045] An embodiment with this feature is illustrated in Hg. 4, where a plurality n of binary outputs BO l ... BOn of the device 10 is connected to a respective indicator, such as light Enitting Diodes (IEDs) 40a, 40b. likewise, a plurality n of binary inputs BH ... Bti is connected to input devices, such as buttons 42a, 42b.

[0046] Binary outputs of the device are equipped with strong breaking capacity in order to be able to drive inductive loads such auxiliary electromechanical relays often used to simulate the primary equipments of the substation for testing purposes.

IT Security - Secure IEC 61850 Substation Network Access Point

[0047] The GOOSE service of the IBC 61650 standard can be used in interlocking based bus bar protection schemes. In this approach the conventional hard-wired blocking signal paths between the switchgear cubicles are replaced with a substation wide Ethernet IAN. Other functions that can be implemented using GO O SE messaging include circuit breaker failure protection, selective arc fault protection, automatic adaptation of the protection system to varying substation and network configurations, control of the arc suppression coil (Petersen coil), and voltage/ reactive power control of parallel power transformers.

[0048] In an IBC 61850 substation, there is a potential security problem involved with directly connecting personal computers (PCs) to the Substation IAN where the GOOSE traffic runs. According to the invention, this security problem is solved by avoiding direct connection of any PC to the substation local area network An embodiment of the invention adapted to solve this problem is illustrated in Hg. 5, showing a power substation, generally designated 60, with circuit breakers 62a, 62b and disconnectors 64a-d. A power substation IAN interconnects the different devices controlling the operation of the breakers, disconnectors etc. by software. The IAN comprises one or more network switches 30, one of which is shown in the figure, and a device 10 according to the invention is interconnected between this switch and a PC 70. The interconnection between the device 10 and the PC is a separate Ethernet connection (PC port), , where private (PC - device) traffic can be communicated and where the GOO SE messages are available because they are transparently forwarded atthe PC port from the IEC 61850 Ethernet port of the device 10 . Thus, there is no direct connection between the substation network and the PC 70, thereby avoiding the above mentioned security problems.

[0049] The sniffing (scanning) of GO O SE messages is performed from the firmware and/ or embedded software of the device 10, where no commercial operative system is installed. The Ethernet port of the device 10 is only capable of detecting/ sending IEC 61850 GO O SE messages, and acts as a "GOOSE message sensor" during the sniffing.

[0050] The detected GOOSEmessages are then sentto the PC application via the completely separated and independent communication link By no means will a PC application not designed by the manufacturer of the device 10 be able to command the invention to send GOOSE messages or any other IP message on the substation bus.

[0051] The invention is also equipped with a self-supervision function dedicated to verify and suppress the network port 12 of the device 10 in case it should send GOOSEmessages with a suspicious high frequency, for instance due to a failure of the device 10.

Pattern recognition algorithm

[0052] So-called Intelligent Electronic Devices (IEDs) are highly advanced protective relay for the protection, control and monitoring of transformers, breakers, transmission lines, capacitor banks, generators and buses. These relays allow multi- object capabilities where several primary apparatus can be protected with a single device, enabling many other intelligent solutions based on functional integration. The IEDs conventionally support the IBC 61850 standard for substation automation, providing extreme intelligence and flexibility that allows for interoperability in communication with other relays and substation automation components.

[0053] However, errors do appear in power substation networks, such as the one illustrated in Hg. 5, and debugging of network messages is today performed using network analyzers. These network analyzers are complex and expensive devices which required high skill to use.

[0054] M order to provide a debugging functionality, the PC software, preferably as firmware of the device 10 contains a special pattern recognition algorithm, which in one embodiment uses cluster approach. This algorithm will allow debugging of the network messages in very complex situations, where often everything looks OKfrom a network analyzer point of view, but IEDs do not respond to GO O SE messages as they are supposed to.

[0055] The method according to the invention will propose to the user which suspect GO O SE messages where he is supposed to investigate on. Considering that the number of GO O SE messages easily reaches the hundreds in a conventional IEC 61850 power substation, the method will contribute to a large saving in the commissioning and troubleshooting time of substations.

[0056] The positions of circuit breakers and other primary objects in a substation have to be sent thro ugh the network bus, such as an IEC 61850 Ethernet bus, and need to be verified that they are sent from the correct IED and that they are received from the correct IED. The device 10 will be a tool for them as well, as it does not need to be interfaced to a test set The device 10 can send a GO O SE message if a binary input 14 is activated or if a button is clicked on the device interface, see the embodiment of Hg. 4, and it can also activate a binary output or activate a "Virtual IED" on the device user interface when a particular GO O SE message is received. This is often enough for the control engineer, who has to easily setup equipment able to send/ receive the desired GO O SE messages.

[0057] It is very difficult today to debug and/ or trouble shoot the horizontal communication based on IBC-61850 GOOSEmessages in a power substation. The horizontal communication is fully described by the so-called Substation Configuration Description (SCD) file, or generically by the Substation Configuration language (SCI) file. Very often a GOOSEmessage sentfrom an IBC-61850 device is "seen" on the network analyzer and everything looks fine, but the device that, according to the SCD or SCLfile, should receive it does not receive it at all.

[0058] Today, this problem is solved by manually breaking down the Ethernet frame, i.e., the GOOSEmessage, in all its components and checking thatall of them are exactly according to what described in the SCD file, which is used to instruct the sender device, the so called publisher, and the receiver device, the so called subscriber, on how the Ethernet frame shall look like.

[0059] Once one or more differences are found between the theoretical GOOSE message derived from the SCD or SCLfile and the published one on the network, i.e., the one sent from the publisher device, the problem is to understand from where the differences come. These differences give a very important indication on where investigation is needed. Ending the mentioned differences is a cumbersome work and may require several hours of investigations with a network analyzer.

[0060] M other words, IEC 61850 network engineers have the problem of understanding why the exchange of signals does not work, usually when the network analysis seems to say that it everything is OK This involves troubleshooting, network monitoring, long comparisons between the SCLfiles and the real frames lhatrun on ihe network There can be a lot of causes that bring to the incorrect operation of the substation horizontal communication, and the method according to the invention will with special pattern recognition algorithms be able to give useful indications to the engineer. Where the method will notbe able to exactly state the cause of the problem, it will be able to address the attention of the engineer on the most suspicious GO O SE messages. I^" the substation network contains 500 GO O SE messages, and the GO O SER will bring the attention on ten of them, it is clear the value of this information for the engineer.

[0061] M the following it will be described how a device according to the invention will manage to give very useful information to the engineer with some particular "system expert' algorithms that will find out differences between detected GOOSE messages on the network and their description on the SCD or SCLfile.

[0062] The device 10 according to the invention implementing the method is adapted to detect GOOSE messages on Ethernetand is also able to read the SCD or SCLfile describing the horizontal communication. The algorithm comprises pattern recognition algorithms that understand if the two GOOSE messages are different, but should be supposed to be the same, in the following "suspectGOOSE messages", or if they are different because it is correct that they are different

[0063] The algorithm presents the user with a list of suspected GO O SE messages, with valuable information on what could be the practical reason or cause for their deviation.

[0064] More in details, the algorithm defines a vectorial space based on the GOOSE attributes and on this space will define a distance (norm). This distance will be calculated for all the pairs of Scanned GOOSE- SCD or SCLGOOSE messages. [0065] A difference is based on a weighting window for each GO O SE parameter used for defining the distance (norm) between different GO O SE messages.

[0066] The more two GO O SE messages are similar, i.e., the smaller distance between the two GO O SE messages, the higher probably that the same GOOSE messages can give problems in the practical implementation, and they are suspect GO O SE messages.

[0067] In the example illustrated in Hgs. 6a and 6b, the designed SCD file GOOSE message (see Hg. 6a), as defined in the SCD or SCLfiles, is correct, but the network scanned GO O SE message (see Hg. 6b) appears without virtual IAN tag, the GOOSE control block name does not contain the mandatory "$ GO $" identifier and the configuration revision of the datasetis different AU other parameters are identical.

[0068] The "distance" (norm) between the two GO O SE messages, i.e., the SCD or SCLfile GOOSE message and the network scanned GOOSE message, with such differences is small, even if three parameters are different, and the algorithms will detect thatthe scanned GOOSE message is actually the SCD file GOOSE message, with some errors due to the sending algorithm in the IED which sends the GOOSE message ($GO$ is missing), probably the Ethernet switch is wrongly configured (LAN tag missing) and probably the sender IED has not been updated with the latest GO O SE message design, because the configuration revision is older than the configuration revision in the SCD or SCLfile.

[0069] It will be appreciated thatthe parameter list will be allowed to grow when the standard will be issued with other releases.

[0070] The algorithm will propose to label the GOOSEmessage 01-0 c-cd-01-00- 02 as a highly suspect message, worth of further investigation. Considering a substation where some hundreds of different GO O SE messages are running, this information will be very helpful for the engineer.

[0071] The pattern recognition algorithm will identify the two above messages as very similar to each others, and it will give a message to the user, such as:

"WAENlNG!

GOOSE MESSAGE 01 -0c-cd-01-00O2, KEIfi 7 O-IECIDO/ IIN0$GO$RE[β70_DI

1) The VLAN is missing in the scanned GO O SE message, probably the switch is wrongly set as it seems it cuts the Virtual IAN tag.

2) The prefix "$GO$" is missing in the scanned GOOSE message, and probably the sender device is wrongly set

3) The Configuration Itevision of the datasetfor the scanned GOOSE message does not match with the configuration revision in the SCD or SCLfile. The latest Horizontal Communication engineering needs probably to be downloaded in the sender IED as it seems to be not up to date.

Hease verify these issues and then try the comparison between SCD or SCLfile and network scanning again."

[0072] There can be different situations, with even more differences between scanned and SCLGO O SE messages, and they will be identified by the algorithm.

[0073] Additionally, the algorithm will allow the user two other possible comparisons:

[0074] 1) Comparison between two different versions of SCD or SCLfiles that should describe the same substation, giving similar helpful information for the engineer and explanations on possible causes that have generated the differences (user message like: "configuration revision has changed in second SCD or SCLfile, probably the engineering of 61850 horizontal communication has been reviewed").

[0075] 2) Comparison between two different network scanning instants, giving to the user helpful information on GO O SE messages that have changed and proposal for tiie cause of tiie differences (user message like: "Some GOOSE messages detected in tiie previous scanning, are missing in tiie today's network scanning. Hυbably some IEDs are outof order, or some IEDs have changed tiieir 61850 configuration").

[0076] Thus, in a very short time tiie algorithm can give essential information on tiie GO O SE message travelling on tiie network, and will be able to pinpoint at tiie engineer where he should concentrate for tiie investigation. This can save hours of work with tiie network analyzer and manual reading of complicated SCD or SCL files.

[0077] Referred embodiments of a device and a method according to the invention have been described. However, the person skilled in the art realizes that these can be varied within the scope of the appended claims without departing from the inventive idea.

Claims

CIAMS

1. A method of detecting errors in an electrical power substation network, comprising the steps of:

- defining a vectorial space based on attributes of the Generic Object Oriented Substation Event messages according to the IBC 61850 Standard,

- reading a first Generic Object Oriented Substation Event message,

- reading a second Generic Object Oriented Substation Event message, and

- defining a distance between the first Generic Object Oriented Substation Event message and the second Generic Object Oriented Substation Event message, using the defined vectorial space.

2. The method according to claim 1, wherein a cluster approach is used.

3. The method according to claim 1 or 2, wherein the reading of a first Generic Object Oriented Substation Event message is carried out from the substation network

4. The method according to any of claims 1-3, wherein the reading of a second Generic Object Oriented Substation Event message is carried out from a SCLfile.

5. The method according to any of claims 14, wherein the step of defining a distance is based on a weighting window.

6. The method according to any of claims 1-5, comprising comparison between two different versions of SCD or SCLfiles.

7. The method according to any of claims 1-6, comprising comparison between two different network scanning instants.

8. The method according to claim 1 , which is implemented in a power substation network

9. A device (10) for converting Generic Object Oriented Substation Event (GOOSE) messages according to the IEC 61850 Standard in an electrical power substation (60), the device comprising:

- a network port (12) adapted to be connected to a digital network,

- atleastone binary port (14; 16), and

- a memory comprising software (18) adapted to provide conversion between a binary signal on the atleastone binary port and a Generic Object Oriented Substation Event message on the network port

10. The device according to claim 9, wherein the atleastone binary port comprises a binary input (14).

11. The device according to claim 9, wherein the atleastone binary port comprises a binary output (16).

12. The device according to any of claims 9-11, wherein the atleastone binary port comprises another separate Ethernet port for transparent GO O SE message one way forwarding.

13. The device according to any of claims 9-12, comprising an indicator for indicating reception of a particular Generic Object Oriented Substation Event message.

14. The device according to any of claims 9-13, adapted to detect Generic Object Oriented Sub station Event messages fro m an IEC 61850 Substation Configuration language (SCI) file format

15. The device according to any of claims 9-14, adapted to cany out scanning of GO O SE messages from a network by means of the firmware and/ or embedded software.

16. The device according to any of claims 9-15, wherein no commercial operative system subject to possible viruses is provided in the device.

17. The device according to any of claims 9-16, wherein the response time for converting Generic Object Oriented Substation Event messages into electrical signals and vice-versa is less than 1 ms, and preferably less than 0.5 ms

18. An electrical power substation (60) comprising a device according to any of claims 9-17.