Empirical models of airflow output and power consumption were developed for series and parallel fan powered variable air volume terminal units at typical design pressure conditions. A testing procedure and experimental setup were developed to test sets of terminal units from three different manufacturers. Each set consisted of two series and two parallel units, each with 8 in. (203 mm) and 12 in. (304 mm) primary air inlets, for a total of four units in each set. Generalized models were developed for the series and parallel units, with coefficients varying by size and manufacturer. Statistical modeling utilized SAS software (2002). Fan power and airflow data were collected at downstream static pressures over a range from 0.1 to 0.5 in. w.g. (25 to 125 Pa) for the parallel terminal units. Downstream static pressure was held constant at 0.25 in. w.g. (62 Pa) for the series units. Upstream static pressures of all variable air volume (VAV) terminal units ranged from 0.1 to 2.0 in. w.g. (25 to 498 Pa). Data were collected at four different primary air damper positions. Data were also collected at four different terminal unit fan speeds, controlled by a silicon controlled rectifier (SCR). The models utilized the RMS voltage entering the terminal unit fan, the 'rake' sensor velocity pressure, and the downstream static pressure. In addition to the terminal unit airflow and power models, a model was developed to quantify air leakage in parallel terminal units, when the unit fan was off. In all but two of the VAV terminal units, the resulting models of airflow and power had R2 values greater than 0.90. In the two exceptions, there appeared to be manufacturing defects: either excessive air leakage or a faulty SCR that limited the effectiveness of the airflow and power models to capture the variation in the data.

Single Duct Variable Air Volume (SDVAV) systems use series and parallel Fan Powered Terminal Units to control the air flow in conditioned spaces. This research developed a laboratory verified model of SDVAV systems that used series and parallel fan terminal units where the fan speeds were controlled by either Silicon Controlled Rectifiers (SCR) or Electronically Commutated Motors (ECM) motors. As part of the research, the model was used to compare the performance of the systems and to predict the harmonics generated by ECM systems. All research objectives were achieved. The CFD model, which was verified with laboratory measurements, showed the potential to identify opportunities for improvement in the design of the FPTU and accurately predicted the static pressure drop as air passed through the unit over the full operating range of the FPTU. Computational fluid dynamics (CFD) models of typical a FPTU were developed and used to investigate opportunities for optimizing the design of FPTUs. The CFD model identified key parameters required to conduct numerical simulations of FPTU and some of the internal components used to manufacture the units. One key internal component was a porous baffle used to enhance mixing when primary air and induced air entered the mixing chamber. The CFD analysis showed that a pressure-drop based on face velocity model could be used to accurately predict the performance of the FPTU. The SDVAV simulation results showed that parallel FPTUs used less energy overall than series systems that used SCR motors as long as primary air leakage was not considered. Simulation results also showed that series ECM FPTUs used about the same amount of energy, within 3 percent, of parallel FPTU even when leakage was not considered. A leakage rate of 10 percent was enough to reduce the performance of the parallel FPTU to the level of the series SCR system and the series ECM FPTUs outperformed the parallel FPTUs at all weather locations used in the study.

With the economic development, the high quality has become a critical issue for service continuous of power companies. To ensure the stable power supply, the asset management of power equipments is applied to prevent the system outage. With voluminous distribution transformers over very wide area, the real time monitoring of temperature has been included in the scope of smart grid. During recent years, the service outage due to transformer overloading has caused customer panic as well as deterioration of service quality. This thesis develops the Transformer Terminal Unit (TTU) by integration of computer chip for power consumption, DSP and sampling circuit of temperature measurement to achieve the functions of real time monitoring of transformer operation condition. When an abnormal operation condition such as overloading or high oil temperature occurs, the TTU can report the contingency back to the control station via the hybrid communication system so that the distribution system operators can take remedy action to prevent the contingency. The actual loading and temperature of transforms are also measured and collected in this study to develop the relationship of temperature and loading levels. By collecting transformer temperature, the power demand of a transformer can be estimated and the load shedding can then be activated to prevent the problem of overloading when the temperature exceeds the operation constraint.

I en fördelarstation i Ellevios elnät i Stockholm har en viktig konfigurationsfil försvunnit. Filen används för att beskriva styr- och kommunikationssystemet för övervakning och fjärrmanövrering av stationen från en driftcentral. Dessutom behöver operativsystemet på en enhet i kommunikationssystemet uppdateras. Det misstänks att konfigurationsfilen som har försvunnit behövs för att genomföra uppdateringen. Det visar sig att konfigurationsfilen inte behövs för att genomföra uppdateringen av operativsystemet. Två metoder utvecklas därför, en för att genomföra uppdateringen av kommunikationsenheten, och en för att återskapa konfigurationsfilen. Den första metoden beskriver hur operativsystemet på en Remote Terminal Unit i ABB:s RTU500-serie kan uppdateras från firmwareversion 11 till version 12. Den andra metoden beskriver hur en fullständig konfigurationsfil, i form av en Substation Configuration Description (SCD) kan återskapas för stationen. Den senare metoden utvecklas specifikt för den enskilda stationen, men skulle kunna vidareutvecklas för att återskapa SCD-filen i fler stationer där samma problem idag finns. Metoden för att genomföra uppdatering av operativsystemet används framgångsrikt för att genomföra själva uppdateringen. Metoden för att återskapa konfigurationsfilen testas genom att en konfiguration för en ny kommunikationsenhet genereras baserat på den återskapade konfigurationen.  Genom att tillämpa dessa metoder kan tillförlitligheten för styr- och kommunikationssystem med IEC 61850-teknologi förbättras. Detta kan leda till ökad tillförlitlighet vid elleverans, eftersom kommunikationssystemet används för att övervaka elnätet och hantera fel genom fjärrstyrning. Detta minskar behovet av fysiska besök till stationen. Rapporten är ett examensarbete för programmet Högskoleingenjör i elektroteknik. Examensarbetet utfördes under våren 2023 på företaget Omexom Sweden. / In a distribution substation in Ellevio's power grid in Stockholm, an important configuration file has gone missing. The file is used to describe the control and communication system for monitoring and remote operation of the substation from a control centre. Additionally, the operating system on a device within the communication system needs to be updated. It is suspected that the missing configuration file is required to perform the update. It turns out that the configuration file is not needed to carry out the operating system update. As a result, two methods are developed: one for performing the update of the communication unit and another for recreating the configuration file. The first method describes how the operating system on a Remote Terminal Unit in ABB’s RTU500 series can be updated from firmware version 11 to version 12. The second method explains how a complete configuration file, in the form of a Substation Configuration Description (SCD) can be recreated for the substation. Although the latter method is specifically tailored for the individual substation, it could be further refined to recreate the SCD file in several other stations with the same issue. The method for performing the operating system update is successfully utilized to carry out the update itself. The method for recreating the configuration file is tested by generating a configuration for a new communication unit based on the reconstructed configuration. By implementing these methods, the reliability of the IEC 61850-based control and communication system can be enhanced. This can lead to improved reliability of power delivery since the communication system is used to monitor the power grid and manage faults through remote control. Thereby, the need for physical visits to the substation is reduced. The report is a thesis for the Bachelor program in Electrical Engineering. The thesis was carried out during the spring of 2023 at the company Omexom Sweden.

Examensarbetet kommer att göra en jämförande analys av driftsäkerhet med trådade signaler till en Remote Terminal Unit (RTU) och en Programmable Logic Controller (PLC) med busstyrning. Rapporten genomfördes som ett uppdrag av Skellefteå Kraft AB för att se om det möjligt att byta till PLC- med busstyrning. Rapporten redogör för grundläggande beskrivning för skillnaden mellan de här två system och kommer att undersöka vilken som är driftsäkrare och lönsammare med hänsyn till krav enligt Svenska Kraftföretagens riktlinjer för dammsäkerhet (Ridas).Med hjälp av kurslitteratur, ABB handboken, internet websidor samt intervjuar med Skellefteå Kraft AB:s personal har arbetets resultat visat att busstyrning med PLC kommer att fungera driftsäkert samt kommer att bli lönsamt jämfört med trådade signaler till RTU. Resultat visat även att det finns ingenting som hindrar att installera busstyrning enligt Ridas men vissa funktioner bör installeras. Rapporten är avgränsat genom att inte ta upp eventuella krav från miljöbalken. / This thesis will make a comparative analysis of the operation safety of the wire connection to Remote Terminal Unit (RTU) and Programmable Logic Controller (PLC) with bus-controller. The report describes the basic description of the difference between these two systems and will explore which is safer and more economic with consideration to qualification according to Swedish energy companies' guidelines for dam safety (Ridas).Through course literature, ABB Bok, internet web sits and interviews with Skellefteå Kraft AB staff the result of this report have been created.The report results prove that PLC with bus-controller will operate operationally safe and profitable compared to wire connection to RTU. Results also showed that there is nothing which prevents to install bus-controller according to RIDAS but certain features should be installed.

In this dissertation, the transformer management system has been developed to monitor transformer over loading and generate warning message in conduit mapping management system (CMMS) of Taipower company. The transformer over loading prediction is performed by both offline and online modes. Performs the transformer loading estimation by using the customer monthly energy consumption in customer information system (CIS) and the connectivity attributes of transformer and customers served in CMMS system of Taipower company. The daily load curve of distribution transformer is derived considering the typical daily load patterns which have been developed in load survey study. The warning message will be generated when the peak loading estimated is lager then the transformer rated capacity. To enhance the accuracy of transformer attributes in CMMS system, the transformer phasing measurement system (TPMS) and the connectivity identification system to identify all of the customers served by each transformer are developed. It is difficult to receive the 1 pulse per second signal form global positioning system for timing synchronization of TPMS measuring units for phasing measurement of transformers located in basement, the temperature compensated crystal oscillation with Fuzzy calibration algorithm is used to maintain the timing synchronization within 10o deviation for measurement period of 2 hours. To solve the incorrect problem of transformer and customer connectivity in CMMS, the power line carrier technology is applied in the design of connectivity measurement system for the identification of customers served by the transformer. The peak loading of transformer is estimated by including the temperature effect and the overloading flag of transformer is displayed on the CMMS automatic mapping system. For the online TLM system, the embedded transformer terminal unit is developed for the real time measurement of transformer loading and insulation oil temperature. For the transformer with abnormal operation condition, the alarm signals will be generated and transmitted to the TLM master station via hybrid communication system for the activation of demand response function to execute the load shedding control of customer loads.

In the power industry, electrical grids are undergoing a modernization intosmart grids. The new smart grids integrate the electrical grid and informationand communication technologies, such as software, automation, and informationprocessing. While enabling remote communication with devices on thegrid, putting the grid online also introduces some major problems, such as therisk of being the target of cyber attacks.In this thesis, a security analysis of the Siemens SICAM CMIC CP-8000 remoteterminal unit, used for remote monitoring and automation of electricalgrids is done. Threat modeling was done to identify vulnerabilities in the system,followed by a penetration test of the web interface, used to configure thedevice, as well as a couple of network attacks. During the penetration test, twocross-site scripting vulnerabilities were discovered, one of which could allowan unauthorized attacker to execute Javascript code in the victim’s browser. Itwas also discovered that a user’s login credentials are leaked in the browserconsole in cleartext when logging in. / I kraftindustrin genomgår elnät en modernisering till smarta elnät. De nyasmarta elnäten integrerar elnät och informations- och kommunkationsteknologi,såsom mjukvara, automatisering, och informationsbehandling. Även omdet möjliggör fjärrkommunikation så introduceras även stora problem när elnätenblir uppkopplade, till exempel risken att bli utsatt för cyberattacker.I detta examensarbete utfördes en säkerhetsanalys av en SICAM CMIC CP-8000 fjärrterminal, tillverkad av Siemens, som används för fjärrstyrning ochautomatisering av elnät. En hotmodell för att identifiera sårbarheter i systemetgjordes, följt av penetrationstesting av hemsidan som används för att konfigureraenheten, samt några nätverksattacker. Under penetrationstestningen hittadestvå cross-site scripting-sårbarheter, där den ena kunde tillåta en oautentiseradangripare att exekvera Javascript-kod i offrets webbläsare. Det upptäcktesäven att en användares inloggningsuppgifter läcktes i webbläsarens konsol iklartext när användaren loggar in.

Cyber-physical systems are networked through IT infrastructure and susceptible to malware. Threats targeting process control are much more safety-critical than traditional computing systems since they jeopardize the integrity of physical infrastructure. Existing defence mechanisms address security at the network nodes but do not protect the physical infrastructure if network integrity is compromised. An interface guardian architecture is implemented on cyber-physical control leaf nodes to maintain process integrity by enforcing high-level safety and stability policies. Preemptive detection schemes are implemented to monitor process behavior and anticipate malicious activity before process safety and stability are compromised. Autonomic properties are employed to automatically protect process integrity by initiating switch-over to a verified backup controller. Subsystems adhere to strict trust requirements safeguarding them from adversarial intrusion. The preemptive detection schemes, switch-over logic, backup controller, and process communication are all trusted components that are separated from the untrusted production controller. The proposed architecture is applied to a rotary inverted pendulum experiment and implemented on a Xilinx Zynq-7000 configurable SoC. The leaf node implementation is integrated into a cyber-physical control topology. Simulated attack scenarios show strengthened resilience to both network integrity and reconfiguration attacks. Threats attempting to disrupt process behavior are successfully thwarted by having a backup controller maintain process stability. The system ensures both safety and liveness properties even under adversarial conditions. / Master of Science