Taking Liberties: The Personal Jurisdiction of Military Commissions

On September 11, 2001, Al Qaeda operatives attacked civilian and military targets on US territory, causing thousands of deaths and billions of dollars of economic loss. The next day, the United Nations Security Council unanimously adopted Resolution 1368 characterizing the attack by Al Qaeda as a threat to international peace and security and recognizing the right of states to use armed force in self defense

Distributed Voltage and Current Control of Multi-Terminal High-Voltage Direct Current Transmission Systems

High-voltage direct current (HVDC) is a commonly used technology for long-distance power transmission, due to its low resistive losses and low costs. In this paper, a novel distributed controller for multi-terminal HVDC (MTDC) systems is proposed. Under certain conditions on the controller gains, it is shown to stabilize the MTDC system. The controller is shown to always keep the voltages close to the nominal voltage, while assuring that the injected power is shared fairly among the converters. The theoretical results are validated by simulations, where the affect of communication time-delays is also studied

Market Integration of HVDC Lines: Cost Savings from Loss Allocation and Redispatching

In the Nordic region, many interconnectors are formed by HVDC links, as Scandinavia, Continental Europe and the Baltic region are non-synchronous AC systems. This paper presents two cost benefit analyses on the utilization of HVDC interconnectors in the Nordic countries: in the first we investigate the utilization of HVDC interconnectors for reserve procurement and, in the second, we assess the implementation of implicit grid losses on HVDC interconnectors in the day-ahead market. The first analysis is motivated by real events in 2018 where the inertia of the Nordic system dropped below a critical level and the most critical generating unit, a nuclear power plant in Sweden, was redispatched to guarantee the security of the system. In order to guarantee system security while reducing the costs of preventive actions, in summer 2020 new frequency products were introduced in the Nordic system: the Fast Frequency Reserves (FFR). HVDC lines, however, can perform similar tasks at lower costs. In our analysis, we are, thus, investigating the cost savings of using HVDC lines for frequency support using their Emergency Power Control (EPC) functionality, instead of redispatching or FFR. The second analysis is based on the proposition of Nordic Transmission System Operators (TSOs) to introduce linear HVDC loss factors in the market clearing. With our analysis, we show that linear loss factors can unfairly penalize one HVDC line over the other, and this can reduce social benefits and jeopardize revenues of merchant HVDC lines. In this regard, we propose piecewise-linear loss factors: a simple-to-implement but highly-effective solution. Moreover, we demonstrate how the introduction of HVDC loss factors is a partial solution, since it disproportionally increases the AC losses. Our results show that the additional inclusion of AC loss factors can eliminate this problem.Comment: Submitted to "CIGRE Centennial Exhibition 2021" on December 15, 2020. arXiv admin note: text overlap with arXiv:1910.05607, arXiv:2001.0066

Static Analysis of Power Systems : Edition 2016 - V2

This is a compendium used in the education at KTH-Royal Inst. of Technology in different basic courses concerning power system analysis.QC 20210428</p

Static Analysis of Power Systems : Edition 2016 - V2

This is a compendium used in the education at KTH-Royal Inst. of Technology in different basic courses concerning power system analysis.QC 20210428</p

Multi-terminal VSC HVDC for the European supergrid: Obstacles

For many, the supergrid is seen as the solution that allows the massive integration of renewable energy sources in the European power system. It connects different remote energy sources to the existing grid while offering additional control. It offers balancing through geographic spread and allows a more diversified energy portfolio. In the meanwhile it increases the security of supply.status: publishe

Influence of the Increasing Non-Synchronous Generation on Small Signal Stability

The increasing installation of aggregated renewable generation based Full Rated Converters (FRC) in current power systems is modifying their dynamic characteristics. This paper analyses the influence of large scale inclusion of non-synchronous generation through back-to-back Voltage Source Converters’(VSC) connection on power systems, by presenting the dynamic changes on inter-area oscillations in different penetration level cases. The aggregated model of VSC units is assumed. The Small Signal Stability Analysis (SSSA) is used to show thedynamic behaviour and presents the performance of the power systems related to the domain frequency modes in a test grid system. From the analysis, it is shown that the mode shapes and participation factors are displaced according to the penetration levels. Eigenvalue sensitivity analysis according to the inertia isalso applied, showing the impact of the large penetration of nonsynchronousgeneration.QC 20141208</p

Survey on Power System Stabilizers Control and their Prospective Applications for Power System Damping using Synchrophasor-Based Wide-Area Systems

Powersystemoscillationdampingremains as one of the major concerns for secure and reliable operation of largepowersystems, and is of great current interest to both industry and academia. The principal reason for this is that the inception of poorly-damped low-frequency inter-areaoscillations (LFIOs) whenpowersystemsare operating under stringent conditions may lead tosystem-widebreakups or considerably reduce thepowertransfers over critical corridors. With the availability of high-sampling rate phasor measurement units (PMUs), there is an increasing interest for effectively exploiting conventionaldampingcontroldevices, such aspowersystemstabilizers(PSSs), by using these measurements ascontrolinput signals. In this paper, we provide a comprehensive overview of distinct elements (or "building blocks") necessary forwide-areapowersystemdampingusing synchrophasors and PSSs. These building blocks together shape a tentative methodical framework, and are disposed as follows: (1) fundamental understanding of the main characteristics of inter-areaoscillations, (2)wide-areameasurement andcontrolsystems(WAMS and WACS) andwide-areadampingcontrol(WADC), (3) advanced signal processing techniques for mode property identification, (4) methods for model-basedsmall-signal analysis, (5)controlinput signals selection, and (6) methods for PSScontroldesign. We also describe the latest developments in the implementation ofsynchrophasormeasurements in WAMS and WACS as well as their prospectives for WADCapplications. This paper serves both to abridge the state-of-the-art in each of these elements, and to accentuate aspiring ideas in each building block.QC 20111212PMU-signal-based control of Power System Stabilizer

Suitable placements of multiple FACTS devices to improve the transient stability using trajectory sensitivity analysis

Trajectory sensitivity analysis (TSA) is used as a tool for suitable placement of multiple series compensators in the power system. The goal is to maximize the benefit of these devices in order to enhance the transient stability of the system. For this purpose, the trajectory sensitivities of the rotor angles of the most critical generators with respect to the reactances of transmission lines are calculated in the presence of the most severe faults. Based on the obtained trajectory sensitivities, a method is proposed to determine how effective the series compensation of each transmission line is for improving the transient stability. This method is applied to the Nordic-32 test system to find the priorities of the transmission lines for installation of several series compensators. Simulation with industrial software shows the validity and efficiency of the proposed method.QC 20140123</p