Interactive Information Visualization for Sensemaking in Power GridSupervisory Control Systems

Christine Mikkelsen ∗ †, Jimmy Johansson†, Mikko Rissanen∗∗ABB Corporate Research, Industrial Software Systems, Sweden

†C-Research, Linkoping University, Swedenchristine.mikkelsen@se.abb.com, jimmy.johansson@liu.se, mikko.rissanen@se.abb.com

AbstractOperators of power grid supervisory control systems

have to gather information from a wide variety of viewsto build situation awareness. Findings from a conductedfield study show that this task is challenging and cogni-tively demanding. Visualization research for power gridsupervisory control systems has focused on developing newvisualization techniques for representing one aspect of thepower system data. Little work has been done to demon-strate how information visualization techniques can sup-port the operator in the sensemaking process to achievesituation awareness. To fill this gap, and with support froma field study, we propose solutions based on multiple andcoordinated views, visual interactive filtering and parallelcoordinates.

Keywords— Human supervisory control systems, sense-making, information visualization, power grid visualization,field study

1 IntroductionHuman Supervisory Control (HSC) system is a general

term for systems that include an automation layer betweenthe human operator and the system [15]. HSC systems canbe found within a wide range of application domains andin this paper we will focus on control systems used for su-pervision of power grids. The main objective for an oper-ator of such control system is to make sure that the powergrid runs in ”normal mode”. That task involves informa-tion and data gathering from several different views of thepower grid. The gathered information is used for buildinga mental model of the situation, a concept referred to assituation awareness [3].

Today’s sophisticated and extremely complex powergrids generate large amounts of data which needs to beanalyzed by power system operators. Analyses of recentblackouts have shown that power grid operators ability tounderstand the situation is crucial and that problems withsituation awareness have been one major factor that has af-fected the propagation of failures [4].

In recent years, sensemaking has been introduced as aprocess that should be considered while designing decisionsupport systems for power grid supervision [4].

”Sensemaking is the active process of building, refining,questioning and recovering situation awareness.” [7]

Sensemaking is related to situation awareness [3] andthe conceptual model of sensemaking presented in [10, 11]defines situation awareness as the product of the sensemak-ing process. Their model is intended to describe the pro-cess of how situation awareness is achieved when the avail-able information is uncertain or conflicting, and maintainedor recovered after a surprising event, which are typical sit-uations that an operator of a HSC system has to deal with.The metaphor frame is used to describe how humans startwith some form of framework to make sense of data andevents. This framework can, in the beginning of the sense-making process, be minimal but it expands and becomesmore elaborate when more data is acquired. The frame isa hypothesis about the connections among data and some-times new information confirms the hypothesis but some-times new data forces the user to reject the frame and thusthe user has to replace it with another.

In this paper, we present findings from a comprehen-sive user study that describes how operators have essentialproblems with navigation and interaction with data in thesystem. Even if new visualization techniques that presentdata in a more intuitive way are used, there is still a needfor intuitive navigation and interaction techniques that sup-port the sensemaking process so operators can understandthe situation and make the right decisions.

We propose visualization solutions for interactive anal-ysis of data in a control environment that support sense-making. The solutions have been influenced by the VisualInformation-Seeking Mantra [16]: ”overview first, zoomand filter, then details on demand” and are based on coor-dinated and multiple views (see [1] for a survey and userguidelines) and dynamic visual queries using parallel co-ordinates [8]. The proposed solutions are the result of anextensive user study with 76 participants from 16 different

power utility control rooms in USA, India, Sweden, UnitedArab Emirates and Oman.

The remainder of this paper is organized as follows.Section 2 describes the fundamental views in the targetedsystem. In section 3 related work on interactive informa-tion visualization methods for power grid supervisory sys-tems is discussed. Details of the method used for conduct-ing the user studies are presented in section 4 and the find-ings from the field studies are together with the proposedsolutions presented in section 5. The proposed solutionsand future work are discussed in section 6.

2 BackgroundAn HSC system for power grid supervision usually in-

cludes the following fundamental views:

Geographical overview This is an overview of the powergrid’s geographical area, see Figure 1a. It includes,for example, transmission lines and substations thatare mapped to their geographical location on theoverview. The purpose of the view is to show over-all status of the grid, for example voltage levels and ifthere are reported alarms in substations.

Single line diagrams (SLD) In addition to the geographi-cal overview there is also a schematic view, called sin-gle line diagram (SLD), over the whole system show-ing more details, see Figure 1b. This schematic viewfocuses on the connectivity in the grid and does notmaintain geographical distance between devices. Theschematic view is also divided in sub-views showingindividual substations with more details about devicesand their status.

Alarm and event lists One of the most important views isthe alarm list, see Figure 1c. The alarm list is usuallya vertical list that represents reported alarms in thepower grid. Each alarm that is reported to the alarmlist has a number of alarm attributes that can be usedfor sorting and filtering. When a device in the powergrid report a value that exceeds one of its limits thenan alarm is sent to the alarm list. Usually a device hasa number of different alarm limits and the first levelis supposed to be used for alerting the operator aboutpotential problems in the future if the value continuesto increase or decrease. In addition to the alarm listthere is usually an event list that includes recordedmanual operations and other types of system events.

Detailed information views The single line diagrams dis-play a subset of available information about devices inthe power grid. The displayed information is typicallynumerical values which operators constantly need tosupervise. Other information that the operator needs

occasionally is displayed in separate detailed informa-tion views, see Figure 1d.

Automatic support function views The supervision of apower grid system is supported by automatic func-tions. One example is a function called contingencyanalysis which analyzes the effect of losing one orseveral transmission lines, due to damage or overload.The results from the automatic support functions are,in some cases, displayed on the schematic views or onthe geographical overview but in some cases only intabular lists, see Figure 1e.

Figure 1: The wide variety of views in HSC systems forpower grid supervision: (a) geographical overview, (b) sin-gle line diagram, (c) alarm list, (d) detailed informationview and (e) automatic support function view.

Figure 1 shows an example subset of views that opera-tors use while supervising a power grid system. Due to thesize and complexity of the physical power grid system theinformation and data is spread over thousands of variousviews in the HSC system. The views represent different as-pects of the system and are used for supervising the statusand for performing manual operations. Most of the tasksperformed by an operator involve some kind of decisionmaking and thus the process of making sense of informa-tion to understand the current situation is very important.

3 Related WorkDuring the last decade, research within power grid op-

erations has focused on how to enhance situation aware-ness. Several visualization techniques have been developedto improve the representation of power grid data.

One early proposed technique for visualizing powersystem data is colour contouring [18]. Colour contour-ing is described as useful for representing voltage levelsin the power grid. This technique has been validated in a

follow-up study on the human factors aspects [13]. Thestudy showed that the colour contouring display attractsthe users’ attention to the worst voltage violations quickerthan the numerical display, but at the cost of worse per-formance when used for solving or removing the voltageviolations. Overbye et al. also found that combining thenumerical display with colour contouring resulted in worseperformance in some situations, than just colour contoursor numerical display alone, and their proposed explanationis that users are not able to ignore one dimension (numbers)while using another (colour contours).

Two other presented visualization techniques are staticor animated arrows that represent power flow, and piecharts that represent the transmission lines’ load percent-age [12].

There are several attempts to utilize 3D views by map-ping power system data to a three dimensional shape that isplaced onto a tilted geographical map or schematics of thepower grid. In some cases the tilted map is a terrain maprepresenting additional aspects of the power grid. [2] useda terrain map in combination with colour contours to visu-alize results of power flow analysis and state estimation.

One example of visualizing the result of a contingencyanalysis is presented in [20]. In this case the presented so-lution also utilizes a third dimension by mapping attributes(height, colour and orientation) of bars, cones and other 3Dshapes onto a tilted 2D plane with a single line diagram.

Thus, different kinds of 3D visualization techniqueshave been presented as solutions to enhance the way powersystem data is presented to the operator but few user studieshave been performed to validate that 3D visual represen-tations actually improve the performance. The user studypresented in [19] only concludes that 3D displays could po-tentially be valuable tools but that more studies are needed.However, a number of situations where 3D can add valueare presented. In particular they highlight 3D representa-tions as a tool for improving the speed of high-level judge-ments of current operating levels in relation to upper andlower limits.

Evaluations of 3D displays in comparison to 2D dis-plays have been done for various other domains with mixedresults. The reason for the variety of conclusions in previ-ous conducted evaluations is discussed in [17] and Small-man et Al. present their own comparison study where theyfound that information about a third dimension can be bet-ter obtained in a well-designed 2D display.

The fact that data in a power grid supervisory systemhas a spatial nature is the background for the work pre-sented in [14]. They suggest several visualization tech-niques for different problems that would benefit from a ge-ographical view. Their main idea is to map power systemdata onto different types of 2D icons within a geographical

map, a similar solution as one of the solutions presentedand compared in [17].

Some of the techniques summarized above, such ascolour contours, animated arrows, 3D bar graphs on tilted2D display and pie charts, have been implemented in powergrid supervisory systems as solutions to fill the need formore intuitive displays that provide operators with bettersituation awareness.

The above summary of previous work shows that re-search within visualization for power grid operations hasbeen focusing on developing visualization techniques thatmap power system information to one separate view forexploring a specific aspect of the data. There is little re-search about how these proposed techniques would fit intothe whole decision making process to support sensemakingin situations when information needs to be gathered fromseveral views.

4 MethodologyTo investigate what operators need in their supervisory

role, and how they operate and make decisions in dynamicand complex systems, the best way is to observe them intheir real environment [21]. Thus a number of field stud-ies were conducted in 2008 and 2010 covering 16 differ-ent power utility control rooms in USA, India, Sweden,United Arab Emirates and Oman. During each visit a se-lection of users, having different roles, were observed andinterviewed. The goal was to gather as much informationas possible about the different users’ tasks and how theywere using the system. How they navigated and interactedwith information in the system to perform their tasks andmaking decisions was of special interest. Different typesof control rooms (managing transmission (EMS) and/ordistribution (DMS) power grids) located in three differ-ent continents was covered to capture differences betweenthem. Figure 2 illustrates the role and geographical loca-tion distribution of the 76 studied users.

Figure 2: Distribution of studied users (roles and geograph-ical location)

We chose to do field studies instead of laboratory stud-ies since it is difficult to replicate a true realistic situationwith all interruptions and conflicting events that are goingon in a control room. In addition, all control rooms havetheir own variations of the system and we were interestedin finding out whether those variations affected the users’way of working. Another issue with laboratory testing isthat it is difficult and expensive to get subjects with theright background to travel to the laboratory site.

The drawback of field studies is the lack of control. Theopportunities for conducting the interviews with operatorswere strongly affected by the control rooms’ organizationand schedule and we had to adjust our methods depend-ing on the available time in the control room and with thedifferent users.

Generally a variation of different protocols for cogni-tive task analysis was used. In some cases a modified boot-strapping protocol [5] was enough to get the overall pictureof the users’ main tasks. In some cases we had the oppor-tunity to observe a user while performing a task where hehad to carefully analyze the situation and make critical de-cisions. In those cases an adapted version of the criticaldecision making method [6] was used to get a deeper un-derstanding of the decisions the user had to make.

We aimed for an individual interview with each user,combined with naturalistic observations but in some casesthe interview had to be done at the same time as the userwas in operation due to the fact that replacement operatorswere not available. Thus the interview was constantly in-terrupted, but that also gave us additional and important in-formation about how the system is used. The individual in-terviews together with the different cognitive task analysisprotocols gave us deeper knowledge about the users’ deci-sion making process. Through the naturalistic observationswe captured basic problems that users had with navigationand interaction with information in the system.

The information we got from the interviews and theconducted observations were mainly recorded with pen andpaper and, in some cases, with permission, they were audiorecorded.

During the following phase, proposed solutions fordealing with the general findings were developed and im-plemented in a prototype. Finally the prototype was usedin a qualitative validation of the results.

5 ResultsSeveral findings could be drawn from the field study,

however in this paper we focus on the issues concerning thenavigation between overview and details and alarm man-agement.

A prototype was created in order to test and verify theproposed solutions during the development phase and inorder to get qualitative response from end-users. The pro-

totype was developed with C# as programming languageand Windows Presentation Foundation (WPF) was used forthe graphical user interface. The GAV Framework [9] pro-vided us with the parallel coordinates control component.

5.1 Overview and detailsHaving an overview of the situation in the power grid

has been highlighted by basically all types of users as crit-ical and the most common views chosen for that purposeare the alarm list, in combination with single line diagrams(SLD). To have a complete overview the operators alsohave to find detailed information in many different viewsand it takes a lot of time and effort to just find the rightviews and place them on the available displays. One op-erator commented on moving from one alarm in the listto the station SLD and to find the right device is one ofthe most time-consuming tasks that operators face. Evenif this statement came from a single operator it could beconfirmed by observing other operators.

Another observation was a problem with the currentfunction that takes the user directly from one alarm to thecorresponding device on an SLD. The new view is openedon top of the alarm list and the user has to rearrange theviews on his available displays to avoid hiding importantinformation on the alarm list. Thus this function is notused very often.

Figure 3: Selection of one alarm in the alarm list automat-ically displays the matching SLD and the device causingthe alarm is highlighted. Other alarms related to the samedevice is also highlighted in the list

Our proposed solution to the above findings is to imple-ment a system based on the concept of multiple and coor-dinated views. Figure 3 displays an alarm list view coordi-nated with an SLD view. A selection of one alarm in thealarm list will make the SLD diagram view automaticallydisplay the matching SLD for the device raising the alarmand with the device highlighted to guide the operator to di-rectly understand where the device is located. Other alarmsrelated to the same device is also highlighted in the list andgives the user an instant way to understand if the alarm is

recurring or what the previous alarm from the same devicewas about.

The geographical overview could also be coordinatedwith the alarm list and then a selection of one alarm in thelist would highlight the related station in the geographi-cal overview. Figure 4 demonstrates that the coordinationshould also work in the opposite direction and a selectionof a station in the geographical overview would highlightthe related alarms in the alarm list and the matching SLDwould be displayed in the SLD view.

Figure 4: Substation selection in geographical overviewhighlights alarms in alarm list and displays the correspond-ing SLD with the alarming devices highlighted

The field studies also revealed a need to show more in-formation about alarms in some kind of overview. Thiswas specifically mentioned by operators in American con-trol rooms. Several operators explained that when they re-ceive a new alarm they have to find the right informationin different places and often scroll down large tabular listsbefore they know what to do and how they should act. Oneoperator would like to be able to extract more informationfrom the overview and mentions which device has causedan alarm as an example. Today, he can only see that infor-mation in the SLDs if he zooms in on the right area. Alsoother operators said that details about devices are hard orslow to find. According to one operator, the SLD shouldshow the details about breakers already in that view insteadof another level of windows on top of a station’s SLD. Oth-ers suggested that if the station name is clicked, the opera-tors should see more detailed data on that station.

The above findings are all related to overview and de-tails on demand and these problems could also be solvedwith the implementation of multiple and coordinated viewssince it provides a direct relation between the overview anddetails about objects and devices. Instead of mapping de-tailed information onto the geographical overview displayor onto the SLDs, making them more cluttered, the usercan easily find more information about an object by select-ing it on the overview or SLD. The coordinated detailedview would then show more information about the object,see Figure 5. If the user selects another object the detailed

view would automatically display the related information.

Figure 5: Selection of a device on SLD automatically dis-play its detailed information view

Another problem that operators expressed is that they”cannot measure disturbance” in general. The overall dis-turbance must be deduced by using a number of differentviews of the system, which is cumbersome. One operatoralso said that ”we have to read all values in SLDs insteadof seeing relevant things directly”. Even if this statementcame from one single operator the observations of the oth-ers confirmed this issue. These findings underpin the needfor having good situation awareness.

Because of the complexity of the system it is difficultto have all needed information in one single view. Insteadthe operator has to navigate through different views andput the pieces of information together. The alarm list viewis, for example, used for identifying what the most recentalarms are about, since it is usually sorted chronological,but to find out where the alarms are located the operatorhas to first look at the alarm list and then find the interestingalarm on the geographical overview or on the SLDs. Thus,to understand where the most recent alarms are located theoperator has to put information from the different types ofviews together and this is a cognitively demanding process.

By coordinating the displays the operator can easily an-swer the following questions: Where are the most recentalarms? How are alarms distributed in the power grid? Isthere a specific part of the grid that is affected? The op-erator can select an alarm in the list and the geographicaldisplay highlights the station having the alarms selectedand the operator can directly see where those alarms arelocated on the SLD.

Coordinated views also solve the problem of cumber-some exploration of various lists in the system. The alarmlist is one example but there are many more. The items inthe lists usually refer to one object in the system and thenormal procedure is to navigate from one item in the list toa detailed view of the object in the SLD. This is done eitherusing a function reached through the context menu that ap-pears when right-clicking on the item or with a direct link.As a result the first view, the list, is either hidden or re-placed by the new view, the SLD. The user must thereforere-arrange the views in order to monitor the list and getmore detailed information at the same time or use back-ward and forward interaction to switch between the listand the details. If the user wants more information aboutanother item in the list the same procedure must be per-formed again and this makes exploration of information atime consuming process. Thus the proposed solution of im-plementing multiple and coordinated views is addressingboth the problem with detailed views hiding the overviewand the cumbersome way of navigating between overviewsand details. The solution also addresses the problem of in-formation scattered in different places in the system andthe need to navigate through a number of views to builda mental model of the situation. Multiple and coordinatedviews support the operator in the sensemaking process byproviding an intuitive way to explore data from differentviews and understand relationships among data.

5.2 Alarm managementOne of the most critical issues that was found from the

field studies were the information overflow that operatorsexperience in critical situations. One operator described aspecific situation when he received over 60 pages of alarmsin 30 seconds. During that situation they missed importantalarms about a transmission line that had a high load.

A major event in the system can be followed by a largenumber of alarms and events reported and the only viewthat operators can rely on in that situation is the alarm list.From the alarm list the operator needs to prioritize and findthe root cause or causes of the problems and understandhow the current situation can be resolved. Thus a largeportion of the operators’ daily work is going through pagesof alarms.

It was also observed that too many alarms seems tomake operators regularly ignore some of them and theyneed to trust their experience to identify the alarms that areessential. The need to manually narrow down alarms wasexpressed by several operators. In every control room ex-cept one, it was specifically mentioned that alarm filteringmust be improved from their existing implementation.

Even if the users clearly expressed the need to narrowdown the alarm list they also highlighted the fact that it isrisky to filter alarms and filtering rules must be considered

carefully since it is crucial that operators not miss impor-tant information. It is not possible to only look at the orderof the alarms to detect the root cause alarm and filter outthe rest.

The alarm limits may also have been configured incor-rectly, which makes it risky to use as the only filtering at-tribute.

Today each alarm is traditionally represented with a rowin the list and has a number of different attributes that aredivided in different columns. Examples of attributes aretime, type and priority. The alarm list can be sorted bythe different attribute columns and there is also a possibil-ity to filter the list by entering limits to the attributes in aseparate dialogue window. This functionality is not usedaccording to the field studies and one explanation for thatis that operators are afraid of missing important informa-tion. For example, if the list is filtered to only show alarmsof priority 1-3, there is a risk that important informationis passing by without notice since alarm limits may havebeen calibrated incorrectly. Each alarm that is reported tothe alarm list has to be acknowledged by the operator totell the system that it has been noticed. Only when it hasbeen acknowledged and when the cause of the alarm hasbeen cleared it disappears from the list.

One comment from an operator was: ”Every alarmcounts in some way”. This comment indicates that op-erators somehow use alarms that they, at first impression,seem to ignore. Even if the operator acknowledges somealarms without any further analysis they are still used in thecreation of the mental model of the situation. Observationsshow that operators need the information hidden in the vastamount of alarms but also that they need an intuitive wayto identify the alarms that they should focus on.

Figure 6: Parallel coordinates display showing alarm itemsas horizontal lines crossing alarm attributes values mappedto the vertical parallel axes

Thus operators need a more efficient and interactive wayof filtering alarms without the risk of removing importantinformation. The proposed solution is to coordinate thealarm list with a visualization technique that also can be

used for interactive filtering of the alarm list. The sug-gested technique is parallel coordinates, see Figure 6, sinceit also can reveal hidden patterns in the huge number ofalarms. In the parallel coordinates display, each alarm at-tribute is represented by a parallel axis and each alarm isrepresented with a line crossing through the vertical axis atthe alarm’s corresponding attribute value. From this viewit is possible to explore alarm patterns and find out if thereseems to be a correlation between some of the attributes,for example alarm type and time.

Figure 7 demonstrates how the alarm list can be nar-rowed down by using the sliders on the vertical axis, in theparallel coordinate graph, representing the alarm attributes.Depending on the situation the user can have the option toeither remove or fade the filtered alarms from the list andfrom the parallel coordinates display. The reason why thefiltered out alarms should be faded out instead of removedis the risk of losing important information that is hidden inthe alarms. The user can focus on a selection of the alarmsbut still keep the overview of all alarms and identify pat-terns.

Figure 7: Interactive visual filtering of alarm list using thesliders in the coordinated parallel coordinate graph

Parallel coordinates is not a suitable representation forall alarm attributes. The location of the object that is send-ing the alarm is, for example, better shown on a SLD or ona geographical map. The solution with coordinated viewssolves this issue since an SLD and a geographical map canbe coordinated with the parallel coordinates display andthe alarm list, see Figure 8. Then the operator can carryout filtering operations by selecting regions of the map orof the single line diagram and look at alarms only from thatspecific region.

Thus, the final solution to coordinate the alarm list witha parallel coordinates display, a geographical overviewand/or a SLD provide the operator with an intuitive way ofexploring many alarms and detecting patterns. It addressesthe need for narrowing down the number of alarms so thatoperators can focus on specific areas without the risk oflosing important information.

Figure 8: A coordinated geographical view provides a wayto interactively filter out alarms based on regions

6 Discussion and future workThe field studies have shown that today the sensemak-

ing process of reaching situation awareness is tedious andcumbersome. Operators are required to put pieces of infor-mation together from disconnected views in the system andthe navigation between overview and details is especiallychallenging.

The developed prototype was presented to end-usersduring three focus groups meetings in USa, India andDenmark (including end-users from the Nordic countries).During the focus group session the end-users had the op-portunity to try out the proposed interactive visualizationtechniques. The qualitative feedback from the end-userswas gathered and will be used to refine the proposed solu-tions.

Overall the users were impressed by the proposed so-lutions and asked if they will be implemented in the realsystem. The users were also asked to fill in a questionnaireabout how they felt about the different solutions. The an-swers from the questionnaire, in combination with verbalfeedback, indicate that the multiple and coordinated viewsand parallel coordinates, in particular, have the potential toenhance the way operators interact with data in the system.

High learning threshold is usually listed as one of themajor drawbacks of parallel coordinates. Thus one of theobjectives with the qualitative analysis of our proposed so-lutions was to find out if the end-users understand the vi-sualization technique and how it can be used. Observa-tions of the users while trying out the prototype, togetherwith verbal feedback and the answers in the questionnairesshow that users understand the parallel coordinates display.They started to discuss how it could be used for represent-ing other types of data in the system. One operator said: -”Iam a part of a group that meets every week to discuss alarmpatterns and parallel coordinates would therefore be verygood for us. I mean having this tool for figuring out whatthe data is trying to tell you.” Another statement made byan operator was: -”The parallel coordinates would be very

good; it would be possible to use this in real time.” Thesestatements indicate that the visualization technique is un-derstood and can probably be used for identifying patternsin the alarms.

Another identified issue were the need to narrow downthe number of alarms in the alarm list. The proposed solu-tion, using parallel coordinates for representing alarms andproviding a visual way to filter the coordinated alarm list,was evaluated in a quantitative and qualitative user study.Preliminary results, so far, indicate that the parallel coordi-nates display coordinated with the alarm list outperformedthe alarm list alone in terms of execution time, correct an-swers to tasks and other usability attributes, in particularfor tasks rated as difficult. The user study did not com-pare filtering alarms and selecting a subset of alarms in theparallel coordinates display alone. Thus the improved per-formance cannot be derived from only the parallel coordi-nates display but in coordination with the alarm list. How-ever, subjective user responses were recorded and com-ments about the alarm list’s strength when it comes to se-quential sorting and the level of details in comparison withthe parallel coordinates display were mentioned. This im-plies that the solution of coordinating multiple views sup-port the user in the sensemaking process by providing away to combine the strength of both representations.

Section 3 demonstrates the tendency to believe that newvisualization techniques are the solution for problems withsituation awareness. Visualization techniques play an im-portant role but a single view containing all possible in-formation an operator needs, to have complete situationawareness, would be to cluttered. The evaluation of colourcontours showed, for example, that the combination ofcolour contours and numerical values had the worst per-formance [13]. When they were separated each of themwas effective but for different situations. This underpinsthe fact that the best solution is to create visualizations thatare effective for representing some aspect of the data andcoordinate them together to build a complete mental modelof the situation.

Adoption of the concept of multiple and coordinatedviews opens up a new way for exploring information andsupporting the operators’ sensemaking process to build sit-uation awareness, not only from one view but from sev-eral. This makes it promising to continue to develop cus-tomized visualization strategies for efficient identificationof specific aspects of the system and by coordination findrelationships between them.

The proposed solutions are based on results from fieldstudies in the power grid system domain. It is possible thatthe proposed solutions could be applicable to other humansupervisory control systems, used in other domains, wheredata and information is spread over a vast amount of vari-

ous views, and where operators need intuitive way of nav-igating between overview and details.

Based on the results obtained in this work we will con-tinue to investigate how multiple and coordinated viewsin combination with existing and new visualization tech-niques can improve operators’ sensemaking process toachieve situation awareness in human supervisory controlsystems. Qualitative and quantitative evaluations of theproposed solutions in real world situations are discussedas the next step, both in the power grid system domain andin industrial process control.

AcknowledgementsWe wish to thank the project leader Dilip Kota for ar-

ranging the field study and making things happen and Mar-tin Naedele, Claus Vetter and Magnus Larsson for support-ing this work.

We would also like to thank Missy Cummings and herresearchers in the Humans and Automation Laboratory(HAL) at Massachusetts Institute of Technology (MIT),and Matthew Cooper at Linkoping University for valuableinput and discussions.

This work was partly supported by the ABB IndustrialSoftware Systems program and partly by the Swedish Re-search Council in the Linnaeus Centre CADICS.

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