Development of a Power Quality Conditioning System for Particle Accelerators (original) (raw)

A Multilevel Power Converter with Integrated Storage for Particle Accelerators

2007 Power Conversion Conference - Nagoya, 2007

The PS accelerator (Proton-Synchrotron) at CERN (European Organization for Nuclear Research) is composed of one hundred magnets connected in series. During a cycle of 2.4 seconds, the active power at the magnets terminals varies from plus to minus 40 MW. As this large active power variation was not acceptable to the electrical network, a motor-generator set (M-G) was inserted between the grid and the load in 1968. The M-G set acts as a fly-wheel with a stored kinetic energy of 233 MJ and the magnets are fed by two 12-pulse thyristor rectifiers. After forty years of operation, the system has to be replaced. This paper presents a possible solution for a power system based on capacitive storage. 1482 61 r-I F.j r-i o r i----14

Modular multilevel converters for hvdc power stations

2014

This work was performed in the frame of collaboration between the Laboratory on Plasma and Energy Conversion (LAPLACE), University of Toulouse, and the Second University of Naples (SUN). This work was supported by Rongxin Power Electronic Company (China) and concerns the use of multilevel converters in High Voltage Direct Current (HVDC) transmission. For more than one hundred years, the generation, the transmission, distribution and uses of electrical energy were principally based on AC systems. HVDC systems were considered some 50 years ago for technical and economic reasons. Nowadays, it is well known that HVDC is more convenient than AC for overhead transmission lines from 800 - 1000 km long. This break-even distance decreases up to 50 km for underground or submarine cables. Over the twenty-first century, HVDC transmissions will be a key point in green electric energy development. Due to the limitation in current capability of semiconductors and electrical cables, high power appl...

Improving the Transient Stability by Modifying the Power Exchange by the HVDC Transmission

2018 20th National Power Systems Conference (NPSC), 2018

The high voltage direct current (HVDC) transmission can significantly influence the transient stability of the power system to which it is connected. This work carries an investigation in which the active and reactive powers exchange by the HVDC converter with the system are modulated to improve the transient stability. For this study, a point to point (PTP) HVDC system connected to WSCC 3 machine 9 bus system is considered. The topology of the HVDC converters are considered to be hybrid modular multilevel converters (MMCs). The simulations are performed on PSCAD/EMTDC platform.

Challenges arising from use of HVDC

Proceedings of the Nordic Insulation Symposium, 2018

Direct Current (DC) power systems have been in use since the early 1880s. However, for more than 100 years the 3 phase AC transmission system has been the dominant transmission system for electric power. The main reason for this is the ease of changing voltage levels and grid connection using reliable AC transformers and breakers. During the last 60 years new converter technology has made HVDC the most efficient and economical long distance point to pointpower transmission transportation. In order to satisfy the growing demand of electric energy consumption, new high capacity multi-terminal HVDC systems need to be developed. This is considered an enabling technology for access to remote renewable energy sources such as off-shore wind farms, hydroelectric power and desert solar plants.This review shows that acceptable solutions have to be found to interrupt HVDC short circuit currents. Higher voltage means that new types of reliable HVDC insulation systems have to be developed, incl...

Review of HVDC control in weak AC grids

Electric Power Systems Research, 2018

Current (HVDC) transmission systems to a weak AC grid has been a challenge in recent years. The main target of this paper is to provide a comprehensive review of the "converter control" approaches for: (1) the Line Commutated Converter (LCC)-based HVDC and (2) the forced commutated converter-based HVDC systems in weak AC grids. The control architecture for each HVDC technology (forced commutated and line commutated) is included. The stability limitations associated with HVDC systems, including LCC-HVDC, Voltage Source Converter (VSC)-based HVDC, and the Current Source Converter (CSC)based HVDC, are elaborated. Moreover, the most recent control approaches for possible integration of LCC-HVDC and VSC-HVDC to very weak AC grids are introduced. Finally, the reliability modeling for each HVDC technology in weak AC grid integration is included for corrective and preventive reliability analysis. The LCC-HVDC technology is the best option associated with high power capacities around 10,000 MW for a bipole configuration [13]. Forced commutated converter-based HVDC is the second type of HVDC transmission which is normally applied for medium power levels up to 1000 MW [13,14]. However, since the advent of Modular Multi-level Converters (MMCs), high power application of VSCs has become a reality [15]. For power transmission lines, the following two different types of converters have been established so far: (1) LCCs, which are Current Source Converters (CSCs) using Thyristor switches, and (2) Voltage Source Converters (VSCs), which use IGBT switches [14]. Other combinations and power electronic switches such as forced commutated converter-based CSCs are possible, but are not common at the

Trends for future HVDC Applications

During their development, power systems become more and more interconnected and heavily loaded. With the increasing size and complexity of systems and as the result of the liberalization of the electrical markets, needs for innovative applications and technical improvements of the grids will further increase. HVDC plays an important role for these tasks. Commercial applications of HVDC started in the 1950ies. In the meantime, HVDC became a reliable and economically important alternative for AC transmission, offering advantages in the operation of power systems in addition to the power transfer. The paper discusses expected present and future HVDC applications. Integration of HVDC into AC systems will be used more frequently as it can simplify the system configuration, control load flow and, at the same time, it improves the dynamic system performance and increases the system reliability. For the interconnection of large power systems HVDC offers technical and economical advantages, especially if the interconnection is weak. The connection of remote power stations to the system, e.g. offshore wind generation, can be effectively put into practice by means of HVDC. Advantages of these applications will be discussed and demonstrated by implemented projects. KEY WORDS: Power system development, use of HVDC, types of HVDC transmissions, integration of HVDC into AC systems, project examples

The New 150 Mvar, 18 KV SVC at Cern: Background, Design and Commissioning

Summary: A new Static Var Compensator (SVC) was designed, installed and commissioned by ABB for CERN's Super Proton Synchrotron (SPS) accelerator. Due to the sensitive nature of the pulsating power converter load for the SPS magnets, very strict requirements were imposed on the stabilization of the 18 kV bus voltage and its harmonic distortion. The adopted solution comprises a 150 Mvar TCR and eight harmonic filters with a total power of 130 Mvar. The paper gives a detailed description of the project background, system design and SVC installation. Finally, the results of the SVC performance tests are presented. Keywords: SVC, FACTS, voltage stabilisation, Thyristor Controlled Reactor, TCR, power quality, pulsating power, harmonics, particle accelerator, particle physics.

Power Electronics for HVDC Grids – an Overview

SUMMARY HVDC grids have significant benefits and will likely play an important role in the future energy system. However, protection and fault handling aspects will be different from those of current ac transmission grids and point-to-point HVDC connections. Therefore, new power electronic solutions will be required to implement these strategies. In the paper different fault handling strategies are identified and the required power electronic hardware to implement these is discussed. The focus is put on solutions that are in actual use or that have been strongly considered for use by manufacturers. Two basic fault handling issues arise when designing an HVDC grid. The first relates to limitation of fault currents fed from the ac side, since conventional VSC HVDC converters lack the possibility to block such currents. Several alternative converter circuits have been proposed to solve this problem. Some of these most important are described and compared. These converter topologies differ in terms of cost and power losses, which is reflected in the comparison. The second issue is related to the disconnection of faulted branches in the grid so that operation can continue. In a dc grid the fault current will not be limited, which means that a fault must be rapidly disconnected, typically within a few microseconds. Therefore a need for fast dc breakers will likely emerge in all more elaborate dc grid configurations. Unlike the case of breaking ac currents, where current zero-crossings occur, fast dc breakers are usually based on diverting the current to an energy absorbing element in the form metal-oxide varistors. This is generally made by power electronic components but the mechanism for doing this differs greatly between the studied concepts. Three different dc breaker concepts that have received significant attention are described and discussed. The three concepts differ significantly in terms of properties and component choice.

Overview and Assessment of HVDC Current Applications and Future Trends

Energies, 2022

High voltage direct current (HVDC) technology has begun to gather a high degree of interest in the last few decades, showing a fast evolution of achievable voltage levels, transfer capacities, and transmission lengths. All these changes occurred in a context in which power system applications are highly dependent on HVDC technologies such as energy generation from renewable sources (e.g., energy generated in offshore wind power plants), power exchanges between asynchronous networks, submarine cables, and long-length transmission overhead lines have become more common worldwide. This paper tries to summarize the current state of HVDC technologies, both voltage-source converters and current-source converters, the main components of converter substations, control strategies, key challenges arising from their use, as well as the future prospects and trends of HVDC applications. This paper represents the first step in setting the background information for analyzing the impact of a VSC-H...