Patent Description:
Substation equipment, such as transformers, circuit breakers, etc. are traditionally monitored by dedicated hardware, software and own interface to provide results, warnings and alarms to the user. The general understanding is that data processing and analysis should be performed locally in the monitoring hardware and the results should be available on the local Human-Machine Interface (HMI) or remotely through web interfaces. This leads the substation owners, operators, or asset health responsible with no choice but to integrate all monitoring results to one common interface or to work with many different interfaces, which in practice result in either inefficient or even no use of such monitoring equipment.

As there could be numerous such monitoring devices for each piece of primary equipment in a substation, keeping track of health status of substation equipment becomes a challenge with many different local HMIs and web interfaces. It could also be challenging to handle cyber security issues when integrating different local HMIs and web interfaces. Substation SCADA systems are currently used either to just tunnel data to other analysis platforms or present status from monitoring equipment.

Hence there is still a need for improved substation monitoring.

<CIT> discloses a system including a power transformer diagnosis and prognosis device having memory circuitry storing a plurality of models, wherein each of the plurality of models comprises correlations between potential combinations of operational and non-operational power transformer data and potential conditions of one or more subsystems of a power transformer and include a physics-based model and an empirical model. <CIT> discloses that the system includes communication circuitry configured to receive a particular combination of operational and non-operational power transformer data related the power transformer. <CIT> further discloses that the system includes processing circuitry configured to provide the particular combination of operational and non-operational power transformer data as inputs to the plurality of models, determine a diagnosis for the power transformer from outputs of the plurality of models, determine a prognosis for the power transformer from the outputs of the plurality of models, and display the diagnosis and the prognosis for the power transformer on a display device.

An object of embodiments herein is to provide efficient monitoring of substation equipment.

According to a first aspect there is presented a method for monitoring substation equipment as defined in claim <NUM>.

According to a second aspect there is presented a SCADA system for monitoring substation equipment as defined in claim <NUM>.

According to a third aspect there is presented a computer program for monitoring substation equipment, the computer program comprising computer program code which, when run on a SCADA system, causes the SCADA system to perform a method according to the first aspect.

According to a fourth aspect there is presented a computer program product comprising a computer program according to the third aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium could be a non-transitory computer readable storage medium.

Advantageously this provides efficient monitoring of the substation equipment.

Advantageously this enables a standardized monitoring of substation equipment using a SCADA system.

Advantageously this enables increased reliability due to conceivably less sensor and monitoring equipment requirements.

All references to "a/an/the element, apparatus, component, means, module, action, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, action, etc., unless explicitly stated otherwise. The actions of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

Any action or feature illustrated by dashed lines should be regarded as optional.

<FIG> is a schematic diagram illustrating a monitoring system <NUM> where
embodiments presented herein can be applied. The monitoring system <NUM> comprises a SCADA system <NUM>. In turn, the SCADA system comprises a SCADA software entity <NUM>, a communication driver <NUM>, a local storage <NUM>, and a pre-processing block <NUM>. In turn, the SCADA software entity <NUM> comprises process object storage <NUM>, an HMI <NUM>, data object storage <NUM>, a data acquisition (DA) client <NUM>, a data analysis block <NUM>, a log <NUM>, and an event generator <NUM>. The SCADA system <NUM> is operatively connected to a piece of substation equipment <NUM>, a historian <NUM>, and a fleet management entity <NUM>. As the skilled person understands, there might be a plurality of pieces of substation equipment <NUM> in the monitoring system <NUM> to which the SCADA system <NUM> is operatively connected.

Processed or raw monitoring signals/data values (e.g. representing values of signals and/or data from sensors, monitoring IEDs, protection IEDs, etc.) of one or more pieces of substation equipment <NUM> (hereinafter for brevity referred to as "substation equipment <NUM>") are provided to the SCADA system <NUM> based on standard substation communication protocols like IEC <NUM>-<NUM>-<NUM>, Modbus, the Distributed Network Protocol (DNP), etc. The signal/data values might be received at the communication driver <NUM>, such as an OPC (OLE for Process Control, where OLE is short for Object Linking and Embedding) server in the SCADA system <NUM>. OPC is a software interface standard that allows Windows programs to communicate with industrial hardware devices. OPC is implemented in server/client pairs. The communication driver 150might be provided as a software program that converts the hardware communication protocol used by a programmable logic controller (PLC) into the OPC protocol, or the like. The communication driver <NUM> provides the data/signals to the local storage <NUM> and the OPC DA client <NUM>.

As disclosed above, there is a need for improved substation monitoring. In more detail, even if substation SCADA systems <NUM> have the potential to host monitoring algorithms of different kind (performing pre-processing, processing and data analysis) and to aggregate all monitored information to provide a common interface to the user/operator alongside control and protection information, they are currently used either to just tunnel data to other analysis platforms or present status from monitoring equipment.

The embodiments disclosed herein therefore relate to mechanisms for monitoring substation equipment <NUM>. In order to obtain such mechanisms there is provided a SCADA system <NUM>, a method performed by the SCADA system <NUM>, a computer program product comprising code, for example in the form of a computer program, that when run on a SCADA system <NUM>, causes the SCADA system <NUM> to perform the method.

<FIG> is a flowchart illustrating embodiments of methods for monitoring substation equipment <NUM>. The methods are performed by the SCADA system <NUM>. The methods are advantageously provided as computer programs <NUM>.

S102: The SCADA system <NUM> obtains parameter values from data/signal values pertaining to parameters monitored in the substation equipment <NUM>. How the SCADA system <NUM> might obtain signals/data values from the substation equipment <NUM> has been disclosed above.

Each parameter value could be directly obtained from one or more data/signal values but also be the result of a combination of one or more pre-processed data/signal values. Further, each data/signal value could be mapped to one or more parameter values.

S104: The SCADA system <NUM> associates each of at least some of the parameter values with at least one attention indicator. S104 might be implemented by the data analysis block <NUM>.

S106: The SCADA system <NUM> determines one attention indicator value for each of the attention indicators by processing those parameter values that are associated with the respective attention indicators. S106 might be implemented by the data analysis block <NUM>.

All attention indicators for all monitored parameter have one and the same nominal attention indicator value acting as a threshold for abnormal behavior of the substation equipment <NUM>.

S110: The SCADA system <NUM> provides an alert indication to the HMI <NUM> when at least one of the attention indicator values is above the nominal attention indicator value. S110 might be implemented by the data analysis block <NUM> in conjunction with the HMI <NUM>.

As a non-limiting illustrative example, assume that the parameter to be monitored is the total power loss in a transformer application, and that <NUM> waveforms (<NUM> voltage waveforms and <NUM> corresponding current waveforms) are measured. From each of these waveforms, the fundamental frequency phasor (amplitude and phase angle, given as a complex number) is extracted during pre-processing and sent to the SCADA system <NUM>. Thus, in total <NUM> data/signal values (one amplitude value and one phase angle value for each of the <NUM> waveforms) are provided and obtained by the SCADA system <NUM>. In the SCADA system <NUM> the total power loss is then obtained by multiplying each voltage phasor with the complex conjugate of the corresponding current phasor, obtaining the phase power, then summing the phase powers on the high voltage side to obtain the total power of the transformer and the same for the low voltage side, and then taking the difference between the total power in and out of the transformer to obtain the total power loss. This difference is then the basis for one attention indicator. Thus, the phasors, or the waveforms they represent, are the data/signal values; the total power loss is one example of a parameter. The same <NUM> complex phasors can be used various combinations to determine also other parameter values and attention indicators.

Embodiments relating to further details of monitoring substation equipment <NUM> as performed by the SCADA system <NUM> will now be disclosed.

In some aspects, parts of the herein disclosed embodiments are implemented in the SCADA software entity <NUM> of the SCADA system <NUM> to provide a standardized solution for uniform substation equipment monitoring, by using programming capabilities provided for in the SCADA software entity <NUM> for pre-processing, processing and analysis of monitored parameters. Furthermore, detailed and fast health status presentation (so-called dialogs) to the user can be built using the visual programming environment of the SCADA software entity <NUM>.

As disclosed above, the substation equipment <NUM> might comprise sensors, monitoring IEDs, and/or protection IEDs. The data/signal values might then be obtained from the sensors, monitoring IEDs, and/or protection IEDs.

In some examples there are at least as many attention indicators as there are monitored parameters (in practice there could be more attention indicators than monitored parameters). That is, if there are <NUM> parameters in the subsystem equipment that are monitored, then there are <NUM> attention indicators or more. However, this does not necessarily mean that <NUM> data/signal values are obtained per time unit (which in turn are mapped to at least <NUM> attention indicator values); the data/signal values could be obtained with different relative frequencies (such as depending on individual sampling periods in the substation equipment <NUM>, the protocol according to which the data/signal values are obtained by the SCADA system <NUM> from the substation equipment <NUM>, etc.). Further, some data/signal values, such as values from tap operations, are only available at irregular time intervals.

In some examples the data/signal values are pre-processed in the SCADA system <NUM>, such as in the pre-processing block <NUM> that fetches the data/signal values from the local storage <NUM>, before being associated with the parameter values. In more detail, according to the type of the signal/data, the signal/data values may be directly linked to the analysis routines in SCADA software (via the DA client <NUM>) or passed through a pre-processing stage to extract relevant parameter values. Examples of pre-processing means are waveform analysis algorithms that extract parameter values from waveforms such as amplitudes, operation times and more. Processor and memory intensive complex pre-processing algorithms can be hosted in hardware of the SCADA system <NUM> and the rest of analysis routines can be coded and hosted within the software environment of the SCADA system <NUM>.

According to the invention the data/signal values are pre-processed by being scaled such that a nominal value of each parameter value is associated with the nominal attention indicator value.

The attention indicator values per monitored parameter might thus be scaled quantities based on the data/signal values. In some examples the data/signal values are scaled with a monitored parameter dependent scaling function.

As noted above, the nominal attention indicator value acts as a threshold for abnormal behavior of the substation equipment <NUM>. Further, all attention indicators have one and the same nominal attention indicator value. In some examples the nominal attention indicator value is <NUM>. Thus, an attention indicator value <NUM> means that the parameter values of that attention indicator is exactly on the allowed limit (regardless of the actual value of the parameter values). This makes it easy to condense all of the individual attention indicator values into one single main individual attention indicator value by taking the largest value in any of them. In some examples it is thus enough just to check the attention indicator having the largest value. That is, according to an embodiment the SCADA system <NUM> is configured to perform S108:
S108: The SCADA system <NUM> checks only whether the largest of all the attention indicator values exceeds the nominal attention indicator value or not. S108 might be implemented by the data analysis block <NUM>.

However, in some examples an alert indication is provided for each attention indicator whose value exceeds the nominal attention indicator value and then the values of all the attention indicators need to be checked.

In some examples the attention indicators (and their values) are linked to the event handing database of the SCADA system <NUM>, which generates and logs events of the monitored parameters. That is, according to an embodiment the SCADA system <NUM> is configured to perform S112:
S112: The SCADA system <NUM> logs each at least one attention indicator (and its value) whose attention indicator value exceeds a particular value. This particular value might be equal to the nominal attention indicator value, or be an integer factor of the nominal attention indicator value. In some examples the logged attention indicator (and its value) is timestamped. The at least one attention indicator (and its value) might be logged in the log <NUM>.

The monitored parameters and analysis results might thereby be available in a standard format if there is a need for communicating them to asset management or fleet assessment system, such as the historian <NUM> or the fleet management entity <NUM>.

As an example, the alert indication is an alarm when at least one of the attention indicator values is at least three times the nominal attention indicator value. The alarm might be triggered as an event generated in the event block <NUM> in conjunction with the data analysis block <NUM>.

As an illustrative non-limiting example, assume that three parameters of the substation equipment <NUM> are monitored; one parameter relating to temperature, one parameter relating to a first voltage, and one parameter relating to a second voltage. For simplicity, assume further that each parameter corresponds to one respective attention indicator (although in practice, it could typically be that one monitored parameter is associated with two or more attention indicators and that there are more attention indicators than monitored parameters). Assume further that the parameter relating to temperature has a nominal value of <NUM> degrees Celsius that corresponds to the nominal attention indicator value <NUM>, that the parameter relating to the first voltage has a nominal value of <NUM> V that corresponds to the nominal attention indicator value <NUM>, and that the parameter relating to the second voltage has a nominal value of <NUM> V that corresponds to the nominal attention indicator value <NUM>. Then, a data/signal value of <NUM> degrees Celsius for the parameter relating to temperature would be mapped to an attention indicator value below <NUM>, a data/signal value of <NUM> V for the parameter relating to the first voltage would be mapped to an attention indicator value above <NUM>, and a data/signal value of <NUM> V for the parameter relating to the second voltage would be mapped to an attention indicator value below <NUM>. Although there are three different parameters of different units and with different ranges, the user would still only need to consider if any of the attention indicators have a value below or above <NUM>.

When needed, a detailed view of analyzed monitoring parameter values, warnings, alarms, etc. might be available to the user through a display at the HMI <NUM>. This view could include history of input data to the analysis algorithms in the SCADA system <NUM>, monitored parameters with their trends and set limits, results in different formats (like tables, pie charts, bar graphs, etc.).

<FIG> and <FIG> show an example in the form of screen captures <NUM>, <NUM> where a substation infrastructure is used to build a complete transformer monitoring system based on voltage and current signals available in protection IEDs. <FIG> schematically illustrates a display <NUM> and HMI components <NUM>, <NUM>, <NUM>, <NUM> which could symbolize any combination of buttons, displays, menu items, lists, etc. <FIG> schematically illustrates a display <NUM> and HMI components <NUM>, <NUM>, <NUM> which could symbolize any combination of buttons, displays, menu items, lists, etc. Pre-processing, processing and analysis of data is performed in the SCADA system <NUM>. In this particular case, transformer performance (impedance, turn ratio, magnetizing current and power loss) as in <FIG> and tap changer operation as in <FIG> are monitored based on phasor and waveform analysis performed in the pre-processing entity <NUM> and SCADA software entity <NUM>.

<FIG> schematically illustrates, in terms of a number of functional units, the components of a SCADA system <NUM> according to an embodiment. Processing circuitry <NUM> is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product <NUM> (as in <FIG>), e.g. in the form of a storage medium <NUM>. The processing circuitry <NUM> may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry <NUM> is configured to cause the SCADA system <NUM> to perform a set of operations, or actions, as disclosed above. For example, the storage medium <NUM> may store the set of operations, and the processing circuitry <NUM> may be configured to retrieve the set of operations from the storage medium <NUM> to cause the SCADA system <NUM> to perform the set of operations.

Thus the processing circuitry <NUM> is thereby arranged to execute methods as herein disclosed. The SCADA system <NUM> may further comprise a communications interface <NUM> at least configured for communications with other entities, systems, functions, nodes, devices, and equipment. As such the communications interface <NUM> may comprise one or more transmitters and receivers, comprising analogue and digital components. The processing circuitry <NUM> controls the general operation of the SCADA system <NUM> e.g. by sending data and control signals to the communications interface <NUM> and the storage medium <NUM>, by receiving data and reports from the communications interface <NUM>, and by retrieving data and instructions from the storage medium <NUM>. Other components, as well as the related functionality, of the SCADA system <NUM> are omitted in order not to obscure the concepts presented herein.

The processing circuitry <NUM>, the storage medium <NUM>, and the communications interface <NUM> collectively implements the functionality of the SCADA system <NUM> of <FIG>.

The computer program <NUM> and/or computer program product <NUM> may thus provide means for performing any actions as herein disclosed.

Claim 1:
A method for monitoring substation equipment (<NUM>), the method being performed by a Supervisory Control And Data Acquisition, SCADA, system (<NUM>), the method comprising:
obtaining (S102) parameter values from data/signal values pertaining to parameters monitored in the substation equipment (<NUM>);
associating (S104) each parameter corresponding to at least some of the parameter values with at least one attention indicator, the at least one attention indicator corresponding to or being based on the parameter;
determining (S106) one attention indicator value for each of the attention indicators by processing the values of the parameters that are associated with the respective attention indicators,
wherein all attention indicators for all monitored parameters have one and the same nominal attention indicator value acting as a threshold for abnormal behavior of the substation equipment (<NUM>), wherein the data/signal values are pre-processed by being scaled such that a nominal value of each parameter is associated with the nominal attention indicator value; and
providing (S110) an alert indication to a human machine interface, HMI, (<NUM>) when at least one of the attention indicator values is above the nominal attention indicator value.