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Inside AKOTRACE® Electrical Heat Tracing System for CSP Plants

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Free e-book about EHT

  1. 1. INDEXINTRODUCTION: Optimization is the key ............................................................. 3A small but key investment for any CSP plant ..................................................... 4Avoiding Poorly Performing CSP plants ................................................................ 5CSP plants: When temperature regulation fails ................................................... 6CSP Plants: Poor planning, poor performance ..................................................... 74+1 key factors to consider in an electrical heat tracing system ......................... 8The structure of an optimal heat tracing solution (I) ........................................... 9The structure of an optimal heat tracing solution (II) ........................................ 10Optimal installation of the Electrical Heat Tracing System (I) ........................... 12Optimal installation of the Electrical Heat Tracing System (II) .......................... 14AKOTRACE® Solution for HTF areas .................................................................... 15AKOTRACE® Solution for Molten Salt areas ....................................................... 16PROTrace®: Control and power cabinets for electrical trace circuits (I) ............ 17PROTrace®: Control and power cabinets for electrical trace circuits (II) ........... 18PROTrace®: Control and power cabinets for electrical trace circuits (III) .......... 19PROTrace®: Control and power cabinets for electrical trace circuits (IV) ......... 20DUOControl Trace: The brain inside AKO´s ProTrace® cabinets (I) ................... 21DUOControl Trace: The brain inside ProTrace® cabinets (II) ............................. 22AKONet Trace, AKO´s control software for EHT systems ................................... 23DUOVision Touch Trace: Designed for small EHT systems ................................ 24AKO´s MI heating cable ...................................................................................... 25Temperature Sensors I ....................................................................................... 26Temperature Sensors II ...................................................................................... 27AKONet Trace: Alarm Management (I) .............................................................. 28AKONet Trace: Alarm Management (II) ............................................................. 29 2
  2. 2. Optimization is the keyOptimizing the performance of a concentration solar power (CSP) plant isessential.Weather a plant uses parabolic cylindertechnology or a concentrating solarpower tower, managing the process oftransforming sun energy into electricity isa tricky task. That´s when an optimumelectrical heat-tracing system comesinto place, especially in thermal storageplants. We know that there are othercomponents that play an important rolein any plant, but this particular one iscrucial because its malfunction can lead to major problems with costly solutions.The transformation of energy is possible thanks to the thermal transfer betweenheat carrier fluids such as steam, thermal oils or molten salts.At the end, is the thermal oil, in the case of parabolic cylinder´s plants, andmolten salts, in solar power tower plants, that by ex-changing heat generatethe necessary steam to drive the turbine that makes electricity.The main function of an electrical heat tracing system is to maintain the righttemperature throughout the process, avoiding solidification of the fluids,whether they are oils or salts.If this crucial component fails, the plant could incur into unexpected expensesor, even worst, it can result in having the plant out of commission for a period oftime.Even with optimum planning, there are always some unforeseen problems thatcan arise during installation, execution and maintenance of any heat tracingsystem, and each one of them could have a different impact on the plant.In following posts we´ll try to analyze some of the most common risks assessedin economic terms. 3
  3. 3. A small but key investment for any CSPplantAn electrical heat tracing system representsjust 0,5% of the total investment in a CSPproject, but its failure could lead to majorlosses that could affect the overallprofitability ratio of the plant. Therefore,optimizing the performance of the electricalheat tracing system is critical to be consid-ered as market leaders. There are, though,some factors that could compromise thisgoal. How?Let´s first make a short list of economic indicators that can determine in anyway the outcome of the expected net production of a solar plant:  Capital expenditure (CAPEX).  Days of production.  Production efficiency (a combination between performance and opera- tional /production costs).And now let´s make a second list, this time of what happens when the electricalheat tracing system is not managed properly or fails unexpectedly:  It raises the plant´s expenses.  It can reduce the performance of the main electrical production systems.  The amount of self consumed electricity of the plant could raise unex- pectedly.  If the breakdown causes a plant stoppage, it would inevitable translate into less production days and major reparation costs.All these factors are directly related to the first list: They all alter the initial planin terms of money and time, and all of the sudden, this 0,5% becomes morecrucial.We have been talking economics, but in our next post we´ll take a look at thetechnical challenges that a plant can face when the electrical heat tracingsystem does not perform as expected. 4
  4. 4. Avoiding Poorly Performing CSP plantsThe scenarios that could lead a CSP plant to perform poorly are diverse.All the components of the plant can be introuble at some point. There are mistakesof a more technical nature, but failurescould also emerge from planning to execu-tion; from maintenance to supervision.Undoubtedly, the electrical heat tracingsystem plays a key role in the overall perfor-mance of the plant. It goes across thepower block (the Thermal Energy Storage, The Heat TransferFluid and theBalance of Plant systems) therefore, from a technical stand of point we aretalking about a wide range of possible breakdowns.Let´s enumerate some of them: (1) Unplanned stoppage when heat carrierfluids get frozen; (2) Loss of performance due to poor temperature regulation ofthe processes (HTF, TES, and BOP); (3) Unsuitable requirements (when the plantis already operational).There is a saying that goes…”Your lack of planning is not my emergency¨. Well,unfortunately in CSP plants, lack of planning is everybody´s emergency. Itrepresents another costly mistake that could prevent a CSP plant to performoptimally. Some other failures of that nature:  Unexpected investments and/or interventions when the plant is fully operational.  Being behind schedule without enough time to react (taking into account that the tracing system is one of the last components to be installed).  Lack of background knowledge to ensure the performance of the plant.  More investment costs (when the engineering part of the process hasn´t been planned properly).Some of these failures could be managed, unexpected problems show up in anyproject, but some of them could be avoided. What we´ll try to analyze infollowing posts is why CSP plants and their electrical heat tracing systems facethese issues in the first place, and then come up with efficient solutions andalternatives. 5
  5. 5. CSP plants:When temperature regulation failsWe continue analyzing ways of avoidingpoor performance in CSP plants and theirelectrical heat tracing systems, focusingtoday on breakdowns caused whentemperature is not regulated properly.One of the worst fears for anyone involvedin a CSP project is having the plant out ofcommission, even for a short period oftime. But unwanted plant stoppages dohappen and bad temperature regulation can be one of the causes leading to thisundesirable outcome. Let´s take a look at what happens when either water orheat transfer fluids freeze. This scenario could present itself when:  The engineering team lacks thermodynamic expertise, that is, do not have enough experience in Thermal Cycles inside CSP plants, undersizing the whole project thus causing system failing.  When the system control solution is weak preventing the staff from receiv- ing valuable, real time information to help them detect and manage on a timely manner a wide range of possible system´s breakdowns  Faulty installation due to lacking of know-how to notice details that are key to the system and a deficient quality control supervisionSuch shortcomings could cause the plant to be out of commission for one daywhich translates into $267,000 in losses. There is more: The additional costs ofrepairing the tracing system and/or damaged equipment could add up to $8.2million.Another issue that could arise regarding temperature supervision is when theestablished system for process temperature regulation (HTC, TES, BOP) is notefficient, resulting in a significant loss of performance. This happens, amongother factors already mentioned in the list above, when the implementedregulation solution is weak. This particular mistake could cause a 5% increase inenergy self consumption of the electrical heat tracing (for each degree increasein temperature in the system´s performance).On our next post, we will analyze what happens when the team in charge of aCSP plant does a poor job planning the project.*Data referring to CSP plants using parabolic cylinder technology with a molten salt storage forup to 7, 5 hours. 6
  6. 6. CSP Plants:Poor planning, poor performanceIt´s only logical: if you don´t plan correctly, youdon´t get the expected results. Breakdowns of atechnical nature are, sometimes, unavoidable. Badplanning is a human error, and such kind ofmistakes seem easier to solve, don´t they? Yes,but let´s be honest, in a CSP project with budgetand time concerns and limitations some of thesimplest principles that we all know “in theory”are rapidly overlooked. All of the sudden solvingthis issue gets complicated.A management team with no experience or thatdoesn´t handle properly a CSP project contributesto:  Applying an ineffective supervision and quality control solution for the plant  A poor execution of an already poor planIf these problems originated because of time related pressures we have somebad news: It turns out that to solve them would take even more precious time.We are talking about delays in the starting of the plant, and since the electricaltracing system is one of the latest components of the plant to be installed, theteam finds itself in a position with not enough leeway to react.As in any other business, loss of time means loss of money. In this case we aretalking about:  The plant could be out of commission for one day which translates into $267,000 in losses.  A 20% capital budget deviation, that is $410,000As we stated at the beginning, poor planning is probably one of the mostcomplicated issues to handle when analyzing critical risks in an inadequateelectrical heat tracing solution, but it is not impossible to solve. If you want tolearn about how to deal directly with these and other challenges related to thedevelopment of a CSP project, we invite you to get familiar with our Akotrace®solution. 7
  7. 7. 4+1 key factors to consider in anelectrical heat tracing systemIn this blog we have already stated how criticalan electrical heat tracing system is in thetemperature control process of any CSP plant.We would like to go deeper into the issue andshare with you the 4+1 key factors we thinkshould be taken into account when choosing ordesigning a heat tracing solution.Energy EfficiencyThis is particularly relevant since the less energy the plant self-consumes, themore energy it has to sell, in other words: Managing energy efficiencyimproves plant´s productivity.Connectivity: Control and MonitoringTo be able to detect a problem in a timely manner gives the plant´s staff theopportunity to react and fix any malfunction in the shortest period of time. Onthe other hand, it is nice to know that everything is working fine, haveperiodical reports to confirm it, and use this information to make furtherimprovements.UsabilityThe staff should be properly trained and the software intuitive enough toprovide a fast response whenever a crisis arises, as well as to manage the day today tasks without a glitch.Safety and ReliabilityYes, the tracing system is no more than 0,5% of the total investment of anyplant, but if it does not work properly the loss of productivity, and of money,can be substantial. A safe and reliable solution makes everybody involved in theplant sleep better at night.An optional one: FlexibilityThis one is up to you, it depends more of your business model. In AKO webelieve that the success of our AKOTRACE® solution relies, in addition to theabove mentioned, on its flexibility to adapt to any project, and to any plant.Whether it uses parabolic cylinder technology or concentrating solar tower,AKOTRACE® is designed to be flexible enough to suit every client´s needs. Theprojects may be different, but the outcome is always satisfactory. 8
  8. 8. The structure of an optimal heat tracingsolution (I)After considering all factors involved in the decision making process whenchoosing an electrical heat tracing solution, it is time to describe how thesystem works. In our case, we want to share with you the structure of our DCSAKOTRACE® solution, a framework that holds three levels of performanceareas designed to fulfill the needs of any CSP plant.Field and installationFrom the base up, Level 3 is made up of all the heat cables and heaters, probes,accessories, lagging, and, in general, of any element necessary for the installla-tion of the tracing system.Control and PowerLevel 2 distributes the necessary power to the tracing system, regulating andcontrolling its delivery according to the information received (thermal probesand electrical supply; safety indicators, etc)Supervision and ConnectivityFinally, Level 1 monitors and supervises the tracing system connecting it to boththe plant´s DCS system and to possible telemanagement points.All three levels of our AKOTRACE® structure are supported by a layer of ser-vices that include maintenance (reactive, proactive and preventive), engineer-ing, project management, installation and implementation.In our next post we´ll do a more detailed analysis of the role each one of thelevels play in the structure of our AKOTRACE® electrical heat tracing system. 9
  9. 9. The structure of an optimal heat tracingsolution (II)The goal of any electrical heat tracing system is to maintain the temperature,avoiding the freezing of either water or heat transfer fluids.How AKO does it? Let us explain in detail the three-level structure of ourAKOTRACE® electrical heat tracing system.Field and Installation (level 3)It´s made up of all the elements in thesystem´s control and is where the elec-trical heat tracing circuit is placed. Itincludes all the necessary field compo-nents, and depending on the processneeds each control can have:  Either standardized or custom made heating elements, depending on the tracing needs, including MI Cable, Self Regulating Cable, heaters and all accessories required for a full installation  Up until 4 thermal probes with different redundancy options, this guaran- tees data reliability.  Current probes that constantly monitor the system´s control energy self- consumption, warning of any drop below certain values, allowing us to identify possible failures in those cases when several tracing sections are integrated into the same system´s controlControl and Power (level 2)In this level our PROTrace® cabi-nets are in charge of monitoringand distributing the power fromthe connection point to system´scontrol. They can have differentmechanism of redundancy to avoidmalfunction in case of failure orduring maintenance. They are fullyadaptable. Based on the applica-tion, our PROTrace® cabinets canbe concentrated in different locations or distributed throughout the field. Theirfinal placement depends on the technical and economical needs of the project. 10
  10. 10. Our system´s control is based on our DUOControl Trace, founded on a PLCPlatform, and integrated into PROTrace® cabinets. It receives data from thethermal probes and power supply, protection conditions, configurationvariables, etc, and it acts accordingly, regulating the output power to reach andmaintain the desirable temperature, thanks to our advanced control algorithms.Inside our PROTrace® cabinets there is the possibility to include the kind ofcontrol, via contactor or SSR; the air conditioning or distribution elements andthe automatic transfer switch.It also accommodates safety and protection elements such as magneto-thermalcircuit breaker, differential circuit breakers protection and a contactor´s securitysystem in each control, adding an extra safety component in case of switcher´sfailure.Supervision and Connectivity (level 1)Our ProTrace® cabinets are stick toeach other with optical fiber connec-tors. Their ring configuration allowsfor non-stop communication in caseof malfunction in one of the links.In this ring configuration we haveour DUOWarm Trace, supervisingkey variables such as power distribu-tion and the environment conditions in the cabinet. It also functions as a gate-way with the plant´s DCS system and with the firewall that allows the internetconnection to manage the installation remotely. It has a redundancy system toavoid communication breakdowns and to facilitate maintenance work.The local operator panel, made up of a PC Panel with our control softwareAKONet Trace, only needs an Ethernet link to the network control DUOControlTrace, allowing for the total control and supervision of the tracing installation.We have just share with you the electrical heat tracing system that makes usworldwide leaders in the sector. We have installed this architecture solution inmore than 25 plants, but we are constantly looking to innovate and find newways to optimize our system and at the same time, the productivity of any CSPplant. 11
  11. 11. Optimal installation of the ElectricalHeat Tracing System (I)We start a series of posts talking aboutthe electrical heat tracing elementsinstalled in the field since the way thetracing system is installed in any givensurface affects the uniformity of thereached temperature.AKO´s experience in this matter, in-stalling our AKOTRACE® solution, themost trusted and used electrical heattracing system worldwide, gives us a unique vision on how to handle thiscritical element in any CSP plant. First of all, before starting any installation it isimportant to double check all materials and plan in advance their distributionfollowing design requirements.Heating cableThe kind of heating cable to be installed should, besides bringing in thenecessary power to compensate thermal loss, endure the maximum processtemperature of the plant.It has to be distributed uniformly, reinforcing its presence in areas with higherprobabilities of thermal loss.If the cable applies more power than it should, the temperature readings will behigher, on the other hand, if it applies less power it can create cold spots,causing problems to the plant´s overall.Special care should be taken when installing the heating cable in critical pointslike pipe junctions, to avoid circuit interference operation.There are some specific criteria to be taken into account when installingredundant heaters, like the distance between themselves or between the cablesand the probes, but in any case, both should behave the same way.The heating cables with mineral insulation should be handled with extra cautiondue to its stiffness, making its handling more difficult.Another important characteristic of the heating cable is that changestemperatures, expanding and contracting constantly, thus obliging theinstallation of an anchoring system capable of enduring such fluctuations.Finally, the tracing system should not represent an obstacle when replacing,when necessary, elements like valves, probes, etc. 12
  12. 12. Temperature probesThe heating elements and the thermal bridges influence the temperaturereadings measured by the probes.A probe that is too close to the heating element causes a lower temperaturereading. On the other hand, if the probe is installed close to a thermal bridge,the temperature reading will be above the required one.If the installation requires probe redundancy, they should be installed depend-ing on the configuration defined by control.In following posts we´ll talk about wiring junction boxes, brackets and how toaudit the installation to ensure optimum plant´s performance. 13
  13. 13. Optimal installation of the ElectricalHeat Tracing System (II)We continue with the series of post westarted a few days ago about the electricalheat tracing elements installed in the field.This time we are going to focus on wiringjunction boxes, brackets and how to auditthe installation to ensure optimum plant´sperformance.Junction boxes and bracketsThe junction boxes, used to connect the heating cables or the temperatureprobes, must be installed in a way that facilitates its access, but, at the sametime, they should be protected from rain and must avoid excessive mechanicalexposure. Extra protection should be added when the boxes are installed in anarea classified as explosive atmosphere.About the brackets used for the boxes set up, (and installed over the surfacewhere it is necessary to control the temperature) we should take into accountthat they could cause additional thermal loss, meaning that this point could getcooler. Depending on the situation it would be convenient the use of anadditional heating cable extension to compensate for possible thermal losses.Compliance checks and installation logsInstallation inspection is carried out in two phases: The first one takes placeafter the installation of the heat tracing system and before lagging.At this time we have to make sure that all the materials used are undamagedand that the installation complies with the established requirements.We should take into consideration that any intervention in the electrical heattracing system after lagging requires its removal, that´s why all the necessarychecks have to be made before. This is a critical reminder since any mistakedetected can be easily corrected at this point, but after lagging, the costs of anyrepair just skyrockets.Among the most important checks we should pay special attention to theinstallation of the heater and its probes, making sure that all elements are fixedcorrectly, properly labeled, and, most especially, they should comply with theproject requirements.That´s what AKO has learnt over years of research and multiple installations,the kind of experience that have made our AKOTRACE® solution the mosttrusted and used electrical heat tracing system worldwide. 14
  14. 14. AKOTRACE® Solution for HTF areasWe continue in this post dissecting our AKOTRACE® Electrical Heat Tracingsystem, focusing now in our solution for HTF areas.First of all, let´s establish three critical issues that our solution takes care of:  Maintenance of temperature between 50 and 60 ºC  Focus on temperature maintenance, no heating  Reduction of heat lossSince in the HTF area we just have tomaintain the temperature, between 50-60ºC, we only need so much power (com-pared to the Molten Salts area) meaningthat the tracing system´s energy consump-tion is also low. This reduces thermal lossin areas with higher levels of exposure,that´s the case of valve bonnets, that doesn´t need any extra tracing.Oscillation levels of temperature in these zones make the ON/OFF regulationthe most suitable solution, with a lower number of commutations (start/stop)from the system, allowing the use of contactors to control it, hence reducingunnecessary costs in components. This kind of regulation is available in ourDUOControl Trace.Occasionally, it may be necessary to integrate several sections of traceconnected to the same system control. In these cases the use of current probesalong with our AKONet Trace system allows us to identify breaks in any of thelegs by detecting a decline in energy consumption.Taking the above mentioned into account, and thanks to the flexibility of ourAKOTRACE® solution, we can reduce costs without losing efficiency, alwaysprioritizing the safety and security of the plant´s process.In our next post we´ll specify how our AKOTRACE® Electrical Heat Tracingsolution works in Molten Salt areas. 15
  15. 15. AKOTRACE® Solution for Molten SaltareasAs we promised, this post will now talkabout our AKOTRACE® Electrical Heat Trac-ing system, for molten salt areas. First weare going to highlight four critical issues thatour solution takes into consideration:  Temperature should be maintained at 265 ºC  There are two kind of tracing circuits: for temperature maintenance and for heating.  Higher levels of thermal loss due to higher temperature readings  Tracing is especially critical in this area and requires a higher level of readiness.Thermal loss is higher in molten salt areas due to the higher levels of tempera-ture readings that should be maintained. Precision is key when regulating thetemperature in this area to be energy efficient and avoid unnecessaryoverheating.The proper regulation algorithm for this application is the Proportional-Integrated (PI), available in our DUOControl Trace, because it allows eachcircuit to be more specific regarding the response speed, and at the same time itachieves a very precise and reliable regulation, which translates intotemperature fluctuations, with regards to the SP, under a 1 ºC. Since the PIregulation means variable connection/disconnection cycles, the commutationelement more suitable is the solid state switch-off relay that allows for anunlimited number of commutations.There are some circuits that require extra power to guarantee two kind ofworking modes: temperature maintenance and heating. Furthermore, thisheating should be done in a limited period of time and making sure not tosurpass the materials design temperature. Our DUOControl Trace applicationhas some functionalities to control the heating process during both the ramp-upand the steady state periods.Due to the extra power, the malfunction of any of the control elements couldcause an excessive temperature increase. To correct this problem, ourAKOTRACE® Electrical Heat Tracing solution offers the option to get a safetycontactor that disconnects temporarily that particular tracing section in case itreaches the “Safety Temperature Reading”, generating an alarm in both theoperator´s local panel and in the DCS.There are some critical points that should be treated in a special manner. Forthese points AKO has specific solutions that have already been used successfullyin various plants. AKO´s vision allows for a more adaptable installation, speciallydesigned to cover any plant´s needs, providing each area the necessaryresources according to its importance or criticality in the production process. 16
  16. 16. PROTrace®: Control and power cabinetsfor electrical trace circuits (I)A very important component in any trace installation is the power and controlcabinet. Its main function consists on monitoring and managing power from thepower supply to the trace circuits, although it can also incorporate subsystemsdepending on the installation needs.AKO has a wide range of cabinets with multiple configurations adaptable to anyinstallation needs. According to its structure they can be categorized by:  PROTrace®: They adapt to each plant´s requirements (tower o parabolic through concentrator) and to the application (molten salts or HTF). They provide a high safety standard because they allow, among other things, power supply redundancy in power connections, power sources and probes, as well as monitoring of the cabinet´s performance.  ProTrace Distributed: Designed for projects where there is a large distance between the trace circuits in the electrical rooms (we´ll talk about these ones in following posts)PROTrace® cabinetsA standard configuration of the cabinets for solar plants (with molten saltsstorage) contains the following components:Connection and supplyInclude all the generic services: Genericprotection, transformers, power supplyfor system´s control and supply networkanalyzers. The power supplies and con-nections can be redundant (we recom-mend it in critical processes). In thesecases it monitors the quality of the net-work to switch from one connection toanother when needed.Trace controlGets the information from different elements of the installation (temperatureprobes and electric current, protections status, framework variables, etc) andacts consequently, modulating the start power in each trace circuit.SwitchingThe circuits get connect or disconnected depending on the information gottenfrom trace control. Depending on the projected switching frequency, that is thepreset regulation algorithm, they can be contractors or SSR (switch-off relays).In our next post we´ll continue outlining more components of our PROTrace®cabinets, including our AKODUO safety system. 17
  17. 17. PROTrace®: Control and power cabinetsfor electrical trace circuits (II)We continue where we left it in our last post, talking about AKO´s PROTrace®cabinets. As we have already stated a standard configuration of the cabinets forsolar plants (with molten salts storage) contains the components alreadymentioned in our last post plus the following:AKODUO SafetyIn case of reaching safety temperature readings, the system disconnects thepower supply in the damaged circuit using a second safety contactor. Thisfunctionality protects both the heating element and where it is installed in caseof malfunction in the switching elements.ProtectionThe cabinets have magneto thermal protection and differentials for both thefuse boxes and the trace circuits.Operator panelThey also have an operator panel to monitor and set up the installationsystem´s control. Its local installation simplifies any maintenance job both in thefuse boxes and the field.Fuse boxes monitoringTo ensure the proper functioning of the cabinet, some points are monitored(detection of stress, generic protection status, internal temperature, etc.)generating alarms both in the DCS and in the operator panel. This allows us todo preventive maintenance, avoiding major problems in the fuse boxes and thetrace installation.CommunicationsThe cabinets include the communicationnetwork switchers from all the elements ofthe system´s control: PLC´s, monitoring,operator panel, getaway link with plant´sDCS, and firewall remote management(when applicable). Communications redun-dancy is available to avoid possible linkbreakages.Cooling and WeldingThey maintain the temperature inside the cabinet within the established rangesin the design phase. It is very common to install the power and control cabinetsunsheltered, making the cooling and welding functions very important to ensurethe right functioning of all its elements. We still have more to say about AKO´scabinets. In some other post we´ll describe our PROTrace® Distributed, part ofour wide range of cabinets with multiple configurations, adaptable to anyinstallation. 18
  18. 18. PROTrace®: Control and power cabinetsfor electrical trace circuits (III)We´ve already mentioned that AKO has awide range of cabinets with multipleconfigurations adaptable to any instal-lation needs. Now we are going to de-scribe our PROTrace® Distributed, a cab-inet designed for projects where there isa large distance between the trace cir-cuits in the electrical rooms.These cabinets differentiate themselvesfrom the rest because they distributepower and control throughout the entireinstallation by means of three different kinds of cabinets:  Main Cabinet: Distributes power to secondary cabinets and it acts as a liaison between the plant´s DCS and the tracing system. It includes a local panel control  Secondary Cabinet: Distributes power and communications generated from the main cabinet to the PROTrace D3 and/or D6 cabinets.  PROTrace D3 and D6 cabinets: They receive power generated from the secondary cabinets and then they apply this power to the tracing system, regulating it according to its configuration and each circuits probe readingsThis structure aims to shorten the distances between the control elements andthe tracing circuits, thus dramatically reducing tracing and installation costs.They are designed for CSP plants with HTF or BOP systems. They are notsuitable in sales or in the process industry.Any change in the main cabinet´s configuration (where we found the panelcontrol) or in the plant´s DCS, will be sent to the PROTrace D3 and D6 cabinetsthroughout a communications network, but, nevertheless, each cabinet isautonomous, meaning that they will be working fine even if the network fails.In our next post we´ll give you more details about our PROTrace D3 and D6cabinets. 19
  19. 19. PROTrace®: Control and power cabinetsfor electrical trace circuits (IV)As we promised in our previous post, we are going now to give you more detailsabout how our PROTrace D3 and D6 cabinets work.They are available with 3 or 6 control outlets (D3: up to 3 circuits and D6: up to6 circuits). Each cabinet has two protection elements, independent from eachother, one aimed to control and a second one to power. It includes a contactorper circuit to regulate outlet power, a CPU, our DUOControl Trace (based in anindustrial PLC, with high levels of availability and reliability) a remote inputmodule Pt100 and a resistance welding with thermostat.Their main functions are:  Circuit alarm management  Start timer circuit to avoid consumption peaks  Temperature supervision per circuit  Independent set point per circuit  2 kinds of control per circuit: ON/OFF and CETA  Independent input per circuit  3 alarm temperature thresholds: mini- mum, maximum and critical (it stops regulation)  Output power set per circuit in case of probe malfunction 20
  20. 20. DUOControl Trace: The brain insideAKO´s ProTrace® cabinets (I)When talking about the structure of anoptimal heat tracing solution we have al-ready highlighted in previous posts theimportance of what we call level 2 of theinstallation, referring to control and powerand where our ProTrace® cabinets areplaced. Within these cabinets is whereyou´ll find its “brain”: Our DUOControlTrace, a device in charge of integrating thelogic of the electrical tracing control, moni-toring the input signals (valves, protection status, alarms) and acting accordinglyon the heating elements.The DUOControl Trace devices have been specifically designed to facilitate theconfiguration and monitoring of the electrical tracing installation. They use PLCtechnology, like control hardware, and they provide a high level of reliability toour DCS-AKOTRACE® system.Among other functionalities they include the following:  4 temperature probes per tracing control, with several redundancy options  Temporary synchronized disconnection for shedding maneuvers  Sequential control connection to avoid consumption peaks  Up to 10 alarm outputs (depending on the configuration)  24 process alarms per tracing control  Independent protection outputs that will disconnect the main output in case of overheating  Theoretical totalizing of consumed energy  Transistor output (TRT) that allows for an unlimited number of maneuvers  It has 1 or 2 current probes per tracing control, allowing for the supervision of consumption in single or three phase circuits.  SD card slot, which allows to upload or to save the controller configuration to simplify start off and substitution operationsIts modular construction makes it adaptable to any installation. It cancommunicate to the DCS plant by means of several protocols: MODBUST/TCP,Profibus, Devicenet, etc.Each controller can manage up to 32 tracing controls, performing activationwork in the heating cables, as well as supervising the protection state and statusvariables in addition to managing the alarm system.In our following post we´ll talk about the 3 regulation algorithms (PI, ON/OFFand CETA) included in our DUOControl Trace devices. 21
  21. 21. DUOControl Trace: The brain insideProTrace® cabinets (II)We continue talking about the structure of an optimal heat tracing solution, butthis time focusing on our DUOControl Trace device, the brain inside ourProTrace® cabinets.We have already stated that depending on the needs of each circuit it has 3regulation algorithms (PI, ON/OFF and CETA)PI ControlIt is the most appropriate controlfor areas that require less tempera-ture variation maintenance from SetPoint.The controller is constantly calculating, according to several variables, thenecessary power to reach and maintain the Set Point temperature, and it alsomodulates the output with short term connection/disconnection cycles.In addition to that, it checks the velocity in which the material gets heated,making sure that it does not exceed its limits.Each DUOControl Trace has 4 customized PI parameter sets that permit toadjust the speed response independently in each control.ON/OFF ControlFit for areas allowing for greater temperature variations from Set Point.The output remains active until reaching Set Point temperature plus thedifferential programmed, once it has reached this point, it remains disconnecteduntil reaching Set Point temperature.CETA ControlThis kind of control is suited to compensate thermal losses based on roomtemperature, avoiding the cooling of fluids inside the pipes.The controller estimates the necessary power to reach and maintain Set Pointtemperature depending on room temperature and modulates the output withlong-term connection/disconnection cycles. 22
  22. 22. AKONet Trace, AKO´s control softwarefor EHT systemsWe have previously stated in several posts that our AKOTRACE® Electrical HeatTracing system is designed in a three-level structure.  Level 3- Field and Installation  Level 2- Control and Power  Level 1- Supervision and ConnectivityIt is in the last level, Supervision and Connectivity, where we find AKO´snewest software to monitor, supervise and control electrical heat tracingsystems.AKONet Trace it´s been designed to be accessible and easy to use, with greatefficiency and enough versatility for optimal performance even in the mostambitious projects.It´s a web application accessible from a PC and remotely from any navigatorconnected to the net, even from your phone. One of its setting options includesthe possibility to receive alerts via e-mail and/or SMS.But there is nothing like a live demo on how the application works to give you abetter sense of its functionality and advantages in any CSP plant´s EHTinstallation.Watch it on YouTube! 23
  23. 23. DUOVision Touch Trace: Designed forsmall EHT systemsWe had previously talked about our DUOControlTrace, which we consider to be the brain insideour ProTrace® cabinets. Now we are going todescribe you one device that works along with it:DUOVision Touch Trace.DUOVision Touch Trace is a 7” high contrasttouch screen that together with DUOControlTrace controllers allows to framework andmonitor small electrical heat tracing installationswith up to 128 tracing controls, or, in other words, each screen can manage upto 4 DUOControl Trace with 32 tracing controls each one.Each tracing control regulates the tracing element´s temperature activating anddeactivating the heating cables, supervising its protections, as well as thedifferent status variables and the alarm management.The screen carries out monitoring and frameworking functions, leaving thetracing management to DUOControl Trace, allowing for the installation to keepon working even when there is a malfunction. Its main responsibilities are:  Creation of tracing control groups when needed: Allows for the organization of different tracing sections in groups, to facilitate its identification during monitoring or frameworking.  Up to 3 user levels, according to its permissions: Visualization, operation and maintenance, which ensures that only qualified people would be able to access and modify tracing installation frameworks.  Easy to use frameworking: Allows to change any installation framework even if you are not familiar with programming.  Graphical identification of control status. Just with a quick look to the screen you can see the installation´s tracing status. When an incident arises (disabled controls, alarms, etc.) the screen will display alarm icons or it will change the regular colors of the control or control group affected by the problem.  SD card slot: Which allows for making system´s configuration backups and restore them when needed, facilitating maintenance work.  Protection level IP 65: Allows for its installation in industrial environments  Easy to connect: It only requires power feed and to be connected to the DUOControl Trace network (Ethernet with RJ45)  Theoretical totalizing of consumed energy: It allows to know the theoretical value of the consumed power.To recap, the DUOVision touch Trace is the ideal alternative to AKOnet Trace,when working in small EHT installations. 24
  24. 24. AKO´s MI heating cableOne of the key elements in any electrical heat tracing installation is the use ofthe right heating cable. In this post we are going to share with you thespecifications of AKO´s Mineral Insulated (MI) heating cable.In any EHT installation, the maintenancetemperature and the process temperaturedetermine the kind of heating cable moresuitable to use.The maintenance temperature is usuallylower than the process temperature, thisfact is determinant to decide the maximumpower that the heating cable can endurewhen connected, while the process temper-ature is needed to avoid the damage of theinsulated cable when it is disconnected.In instances when process temperature reaches 450 ºF readings, or when themaintenance temperature is around 350 ºF, which requires high power from theheating cable, it gets really difficult to pick the right heating cable.But AKO´s heating cable with mineral insulation can be used in process temper-ature readings of up to 1100 ºF and in maintenance temperature around 900 ºF.Some other specifications of this cable, besides the power and temperaturerequirements, are, among others:  Corrosion resistance  Mechanical resistance  Usable in explosive atmospheres  Easy to useWhen the corrosion is high, the cable is made with a cover with a high nickelcontent (Alloy 825). AKO´s MI cable also has a high mechanical resistance, andat the same time, it is adaptable to the surface in which it has to be applied.The heating element varies regarding the material or diameter depending onthe lineal resistance we want to achieve. The material used is a mixture of nickelwith other metals.The heating cable has a heating zone and one or two cold ends to be connectedto the power supply. When the cable is 1 core, it has two cold ends for powersupply, while the 2 cores cable just has one cold end. When assembled in thepower supply, each cable´s cold end includes a cable gland.The insulation between the cable´s active part and its cover is made out ofMagnesium Oxide (MgO).AKO´s heating cables with mineral insulation are certified to be used inexplosive atmospheres classified as Class 1 Division 2, Groups A, B, C & D. 25
  25. 25. Temperature Sensors IIn this post we will now talk about the different kind of probes used in tracinginstallations and which one works better depending on the circumstances.Which probe to use and whenIn order to install an electrical trac-ing to maintain a given temperature,it is required the installation of acontrol loop with a signal providedby a temperature sensor.When selecting the temperature sensors we have to take into account the tem-perature ranges they will have to endure since the process temperature tendsto be higher to the temperature to be maintained by the electrical tracing.When the temperature ranges are about -60 ºF and 1100 ºF, the temperaturesensor more suitable is a Pt100 probe. For readings higher or closer to theprovided temperature, such is the case of solar thermal power tower plants, it´sbetter to use a type K thermocouple sensor.The placement of the sensors on the field close to the traced surfaces entailsthat they have to be extended to the installation´s electrical cabinets. Whenusing Pt100 probes we recommend a converter to 4-20mA, making it evenmore necessary when installing type K thermocouples. The 4-20 mA signalavoids temperature measurement mistakes caused by possible electromagneticinterferences, which makes its application very common in industrialenvironments.AKO has convertors for both Pt100 probes and type K thermocouples to4-20 mA placed in connection boxes to facilitate its installation.In our next post we´ll talk about redundancy and the required temperature indifferent points. 26
  26. 26. Temperature Sensors IIWe continue analyzing the kind of probes used in tracing installations and whichones are more suitable depending on the circumstances.Where to install a temperature sensorNow we are going to focus in temperature measurement in different points ofthe tracing system and its redundancy. Usually there is a temperature sensor ineach control area of an electrical tracing installation. But, depending on thecriticality of the set up it could be necessary the installation of several sensors inthe same area. The distribution of these sensors is made in three different waysdepending of the installation´s design requirements:  In a redundancy point  In several points without redundancy  In several points with redundancyOur controller DUOControl Trace allows for the configuration of the mentionedsensors, and it controls the system based in its temperature readings. Anytemperature deviation above a determined value or the damage of a sensor willtrigger distinct alarms allowing for a faster and more precise identification ofthe problem.In our next post we will talk about AKONet Trace, our software that monitors,supervises and controls electrical heat tracing systems. We will explain in detailhow the alarm system works and we will highlight its mobility. 27
  27. 27. AKONet Trace: Alarm Management (I)We have already described some ofthe advantages of our AKONet Trace,the software that allows for theconfiguration and monitoring ofAKO´s electrical tracing installations.In this case we will focus in thealarm management´s functionality.In any electrical tracing installationthe prompt detection of any sys-tem´s anomaly is vital, to bothensure a proper plant´s performance and to avoid future greater and costlierbreakdowns. For that reason AKO has been working relentlessly to provideAKONet Trace software with the right tools to manage this kind of incidents in arapid and efficient manner.In case of detecting any anomaly (such as higher or lower temperature readings,mistakes in probes readings, communications breakdowns, etc.), the systemactivates an alarm that gets displayed on the screen in different ways:  Alarm notification bar: Located in the upper side of the screen, it shows the active alarms in sequence. Pressing over any of the alarms it is possible to gain direct access to the alarm´s listing screen that provides detailed information about the active alarms, offering the possibility to confirm it or get access to the strained control.  Alarm´s listing: It shows the entire installation´s alarm listing, being even able to filter the results throughout different parameters (by dates, by active alarms, by pending confirmation, etc.) The results can be exported to PDF or Excel, facilitating its analysis in operating reports.In our next post we will continue describing more functionalities of the softwareincluding how it works with the system´s control and the categorization of thealarms depending on its source. 28
  28. 28. AKONet Trace: Alarm Management (II)We continue with the analysis of ourAKONet Trace, the software that allowsfor the configuration and monitoring ofAKO´s electrical tracing installations.We had previously described two dif-ferent ways the software has to displaythe alarms on the screen: by means ofan alarm notification bar and with analarm´s listing.Now let´s see how the software works with the system´s control, plus we willshow you how it categorizes the alarms depending on its source.  Control´s active alarms: When reviewing the details of any system´s control, you can detect all the active alarms and even confirm them in case it is necessary.  Alarm´s icons: There are 3 alarm´s icons depending on where they were originated:  I/O Service: Alarms that detect malfunctions in the elements inside the electrical cabinet: internal temperature and electrical protection status of the different electrical elements.  Generics: This kind of alarm gets activated by a cluster, meaning that it can affect all the tracing circuits controlled by the cluster.  Control: An alarm generated by any of the installation´s tracing controls. It also displays an alarm icon in the strained control. When monitoring groups or cabinets, this same icon gets displayed in the strained group or cabinets.In addition to the above mentioned, to facilitate the problem´s resolution,besides indicating the cause of the alarm, the software also displays the nameof the PLC affected, the name of the control and to which group it belongs, plusthe time and date it was generated. These data allows the maintenancepersonnel to locate and repair the breakdown in a very short period of time.What´s more, apart from being able to view the alarms in the PC panel whereAKONet is executed, all the alarms are communicated to the DistributedControl System (DCS), in exceptional cases when the client demands having thetracing system´s control connected to the DCS. 29
  29. 29. AKO ENGINEERING INC. 1490 South Price Road | Chandler | AZ 85286 Suite 311 | USA Tel. (1) 480 428 5083| e-mail:|www.akotrace.comWe reserve the right to supply materials that might vary slightly to those described in our Technical Sheets.Updated information is available on our website: