The European energy transition is leading to a transformed electricity system, where Distributed Energy Resources (DERs) will play a substantial role. Renewable Energy Sources (RES) will challenge the key operational obligation of real-time balancing and the need for flexibility will consequently increase. The introduction of a local flexibility market (LFM) would allow the trading of flexibility supplied by both producing and consuming units at the distribution level, providing market access to DERs, a support tool for Distribution System Operators (DSOs) and a value stream for energy suppliers. Aggregators and DSOs for different reasons can enhance the valuation of flexible DERs. Several research papers have assumed aggregators fully interacting with the electricity markets and DSOs contracting services with power system actors. These interactions are still not allowed in many European countries. This article aims to analyze the European regulation to identify the most important enablers and pave the way towards the full exploitation of DER flexibility, culminating in the establishment of an LFM. Therefore, three main stages, emerging from the progressive withdrawal of the current regulatory and market barriers, are identified: (1) enabling the aggregator’s trading, (2) evolution of the DSO’s role, and (3) key-design challenges of an LFM.

X-ray emission has been detected occasionally during the streamer-corona propagation in a wire-plate corona reactor open to ambient air. A 65 kV pulse with 15 ns rise time is applied to the wire anode superimposed on a 20 kV dc bias. The duration of the driving voltage pulse (110 ns) is less than 2.5 times the primary streamer transit time. Under this condition no arc discharge occurs between the wire and the cathode plates separated by 6 cm air. The onset of x-ray emission coincides with the initiation of the primary streamers near the wire anode. No x-rays were detected later, during or after the primary or secondary streamer development. X-ray energies ranged between 10 and 42 keV, as detected by a LaBr3 (Ce) scintillator–photomultiplier combination. Time resolved imaging of the streamer propagation highlights the different stages in the streamer discharge process. The energetic electrons originate near the anode, at the moment of streamer initialization.

Plasma activated deionized water from a hot arc 150 W PAW synthesizer has been analyzed for nitrite, nitrate and peroxide densities. Observed nitrite and nitrate levels are impressive, reaching several millimoles per liter at few hundred kiloJoules per liter energy input. Nitrate levels appear positively influenced by the applied energy density, together with a less pronounced increase in nitrite levels and limiting energy density for maximum peroxide levels. Active PAW cooling during synthesis appears to be essential for obtaining relevant peroxide levels and connected PAW activity. In addition to established laboratory diagnostics, alternative low access tools have been investigated for applicability of PAW characterization in offlab situations. Although no unique parameter exists to properly represent PAW activity, pH, oxidizing-reduction potential and electrical conductivity provide important insight, together with aqueous phase nitrite absorption spectrometry. Finally, classic acid-base titration has been applied to find access to the complex mixture of acidic reactive nitrogen species. Keywords Plasma activated water • Reactive oxygen species (ROS) • Reactive nitrogen species (RNS) • Reactive oxygen and nitrogen species (RONS) • Wet chemical analysis • Atmospheric plasma liquid interaction • Pulsed power plasma technology

• A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. Abstract-In this paper, we present a large-bandwidth, highcurrent and high-voltage measuring system for pulse measurements in pulsed power systems. The developed sensors can be easily calibrated, require no extensive (3D) modeling, are very compact, are inexpensive, and have a bandwidth of up to several GHz. Moreover, they can be used in any pulsed power system where a pulse source is connected to its load by a coaxial cable (without disturbing the coaxial geometry).We developed this sensor system for use with our nanosecond pulse source system. The type of sensors we used are Ddot and B-dot sensors, which are compactly mounted on the coaxial cable that connects our nanosecond pulse source to its load. This enables us to measure the characteristics of each sensor very precisely with a vector network analyzer. With these characteristics -combined with the characteristics of the measuring cable assembly -we can numerically reconstruct the voltage and current waveforms that passed the sensor positions. Our calibration approach, the mounting on the coaxial cable and the post-processing of the results make these sensors very flexible. While we use the sensors for energy measurements, camera triggering and the general measurement of the pulses, other researchers can use these type of sensors as well in any system where a (coaxial) cable connects a pulse source to its load.

• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication Citation for published version (APA):Huiskamp, T., Sengers, W., Beckers, F. J. C. M., Nijdam, S., Ebert, U. M., van Heesch, E. J. M., & Pemen, A. J. M. (2017). Spatiotemporally resolved imaging of streamer discharges in air generated in a wire-cylinder reactor with (sub)nanosecond voltage pulses. Plasma Sources Science and Technology, 26(7), 075009. DOI: 10.1088/1361-6595/aa7587General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract. We use (sub)nanosecond high-voltage pulses to generate streamers in atmospheric-pressure air in a wire-cylinder reactor. We study the effect of reactor length, pulse duration, pulse amplitude, pulse polarity, and pulse rise time on the streamer development, specifically on the streamer distribution in the reactor to relate it to plasma-processing results. We use ICCD imaging with a fully automated setup that can image the streamers in the entire corona-plasma reactor. From the images, we calculate streamer lengths and velocities. We also develop a circuit simulation model of the reactor to support the analysis of the streamer development. The results show how the propagation of the high-voltage pulse through the reactor determines the streamer development. As the pulse travels through the reactor, it generates streamers and attenuates and disperses. At the end of the reactor, it reflects and adds to itself. The local voltage on the wire together with the voltage rise time determine the streamer velocities, and the pulse duration the consequent maximal streamer length.Spatiotemporally resolved imaging of streamer discharges in air generated in a wire-cylinder reactor with (sub