Investigating the impact of asset condition on distribution network reconfiguration and its capacity value

Ph. D. ThesisGenerally, decisions regarding Distribution Network (DN) operations are based only on operational parameters, such as voltages, currents and power flows. Asset condition is a key parameter that is usually not considered by Network Management Systems (NMSs) in their optimization process. The work in this thesis seeks to quantify the extent to which asset condition information can positively influence network operation and planning; specifically through Distribution Network Reconfiguration (DNR). Asset condition can be translated into Health Indices (HIs) and failure rates, allowing an NMS – or an optimization algorithm – to make better informed decisions. This is realized via appropriate asset condition assessment and failure rate models. The effect on optimal DNR is evaluated – focusing on substation condition and reliability; the idea of load transfer from one feeder or substation to a more reliable one is key in the proposed methodology. Condition-based risk is considered in the DNR problem, and the impact of transformer ageing on network reconfiguration is examined as well. The effect of asset condition assessment and ageing – which depends on the type of network branches (overhead lines or underground cables) – on the optimal distribution switch automation is also investigated. Finally, a probabilistic method is developed to quantify the contribution of DNR to network security considering asset condition and ageing. The results show that savings can be in the order of tens of thousands of U.S. dollars for a single DN; this corresponds approximately to 10% of the annual cost of active power losses. This can mean hundreds of thousands – or even millions – of U.S. dollars of savings for a single DN operator. Regarding the optimal placement of automated switches, neglecting the effect of asset ageing can result in an underestimation of expected outage cost by as much as $223,000 over a 20-year period. Finally, ignoring the contribution of DNR to security of supply can double the estimation of network risk; in addition to that, disregarding asset condition and ageing results in a reinforcement deferral overestimation of two years

On the definition and observability of the neutrino charge radius

We present a brief summary of recent results concerning the unambiguous definition and experimental extraction of the gauge-invariant and process-independent neutrino charge radius.Comment: 5 pages, no figures, talk presented at the XXX International Meeting on Fundamental Physics, IMFP2002, Jaca (Huesca), January 28th -- February 1st, 200

Comparative analysis of services from soft open points using cost–benefit analysis

Soft Open Points (SOPs) are power electronic-based devices which can replace Normally Open Points (NOPs) in distribution networks. They can improve network performance by enabling controllable power transfer between adjacent feeders. This flexible meshing can provide a wide range of services, including loss reduction, reduced renewables curtailment, improved reliability, reinforcement deferral, or enabling flexibility services. This paper proposes a novel framework, based on the Cost–Benefit Analysis methodology, to quantify and compare the cost-effectiveness of SOPs for providing each of these five value streams. The framework includes the development of mathematical models that encapsulate the key variables that drive competitive SOP use cases, as well as providing detailed analysis to determine quantitative estimates for each of the parameters. Results suggest that, whilst all services could be cost-effective, that reinforcement deferral and reduced DG curtailment are most likely to find wide usage. It is also suggested that the fast response time of SOPs as compared to conventional NOPs is unlikely to be a viable value proposition for improving reliability via conventional loss of load metrics such as energy not supplied. A detailed case study demonstrates that in marginal cases, where a SOP has a similar system net benefit compared to Business-as-Usual, that all services need to be considered rather than just single value streams in isolation. It is concluded from the research that there are multiple potential competitive applications for SOPs in future distribution networks.</p

Higgs triplet effects in purely leptonic processes

We consider the effect of complex Higgs triplets on purely leptonic processes and survey the experimental constraints on the mass and couplings of their single and double charge members. Present day experiments tolerate values of the Yukawa couplings of these scalars at the level of the standard electroweak gauge couplings. We show that the proposed measurement of the ratio R_{LCD}=\sigma (\nu_{\mu}e)/ [\sigma (\bb\nu_{\mu}e) + \sigma (\nu_e e )] would allow to explore a large region of the parameter space inaccessible to the usual ratio R=\sigma (\nu_{\mu}e)/\sigma (\bb\nu_{\mu}e).Comment: 14 pages, LaTeX, Three figures included using uufiles. A postscript version is available at ftp://ftp.ifae.es/preprint/ft/uabft378.p

The electroweak form factor \hat{\kappa}(q^2) and the running of \sin^2 \hat{\theta}_W

Gauge independent form factors \rho^(e; e) and \hat{\kappa}^(e; e)(q^2) for Moller scattering at s << m_W^2 are derived. It is pointed out that \hat{\kappa}^(e; e) is very different from its counterparts in other processes. The relation between the effective parameter \hat{\kappa}^(e; e)(q^2,\mu) \sin^2 \hat{\theta}_W(\mu) and \sin^2 \theta_eff is derived in a scale-independent manner. A gauge and process-independent running parameter \sin^2 \hat{\theta}_W (q^2), based on the pinch-technique self-energy a_{\gamma Z} (q^2), is discussed for all q^2 values. At q^2=0 it absorbs very accurately the Czarnecki-Marciano calculation of the Moller scattering asymmetry at low s values, and at q^2 = m^2_Z it is rather close to \sin^2 \theta_eff. The q^2 dependence of \sin^2 \hat{\theta}_W (q^2) is displayed in the space and time-like domains.Comment: A new paragraph has been inserted at the beginning of the discussion in Section

On the observability of the neutrino charge radius

It is shown that the probe-independent charge radius of the neutrino is a physical observable; as such, it may be extracted from experiment, at least in principle. This is accomplished by expressing a set of experimental neutrino-electron cross-sections in terms of the finite charge radius and two additional gauge- and renormalization-group-invariant quantities, corresponding to the electroweak effective charge and mixing angle.Comment: 10 pages, 1 figure; a typo in Eq.1 corrected, some comments adde

A reliability-aware chance-constrained battery sizing method for island microgrid

Island Microgrids can coordinate local energy resources, provide post-fault reliability improvements for local customers, and aggregate local power and energy resources to offer services to the wider system. A crucial component of an Island Microgrid is the battery energy storage system, which can manage local imbalances, alleviate constraints, and improve reliability by enabling post-fault islanding. A planning and sizing method is required to quantify and maximize the benefits of battery energy storage while avoiding over-investment and under-utilization. This paper combines comprehensive reliability assessment with chance-constrained convex optimization, via second-order cone programming, to optimally size energy storage within an Island Microgrid. Chance constraints are applied to the battery state-of-charge to avoid sizing the energy storage to accommodate extreme cases of uncertainty, avoiding uneconomic investment. The probability of reaching a state-of-charge constraint also indicates the likelihood that the battery energy storage system will be unable to facilitate island operation in the event of an outage, which affects the Island Microgrid reliability. The method is demonstrated on a real Austrian distribution network as part of the MERLON project. Results illustrate that an optimal trade-off can be identified between system reliability and operating cost when the probability of violating the chance constraints is 4.8%

The neutrino charge radius is a physical observable

We present a method which allows, at least in principle, the direct extraction of the gauge-invariant and process-independent neutrino charge radius (NCR) from experiments. Under special kinematic conditions, the judicious combination of neutrino and anti-neutrino forward differential cross-sections allows the exclusion of all target-dependent contributions, such as gauge-independent box-graphs, not related to the NCR. We show that the remaining contributions contain universal, renormalization group invariant combinations, such as the electroweak effective charge and the running mixing angle, which must be also separated out. By considering the appropriate number of independent experiments we show that one may systematically eliminate these universal terms, and finally express the NCR entirely in terms of physical cross-sections. Even though the kinematic conditions and the required precision may render the proposed experiments unfeasible, at the conceptual level the analysis presented here allows for the promotion of the NCR into a genuine physical observable.Comment: 34 pages, 5 figure

On a Neutrino Electroweak Radius

We study a combination of amplitudes for neutrino scattering that can isolate a (gauge-invariant) difference of chirality-preserving neutrino electroweak radii for $\nu_\mu$ and $\nu_\tau$. This involves both photon and $Z_\mu$ exchange contributions. It is shown that the construction singles out the contributions of the hypercharge gauge field $B_{\mu}$ in the standard model. We comment on how gauge-dependent terms from the charge radii cancel with other terms in the relative electroweak radii defined.Comment: 16 pages, revtex with embedded figure