Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userEffects of solar activity on disturbances in Czech power grid: A preliminary assessment (in Czech only)
338
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
English: Solar eruptive events affect the close neighbourhood of the Earth. They also affect human infrastructure, power grids mainly, due to the induction of electrical currents. Only recently the attention was drawn not only to large flares, but also to estimate the long-term effects of increased solar activity by statistical methods. We analyse the failure rates in the main Czech power transmission system operated by the Czech national operator v{C}EPS. We show that the effects of solar activity on failure rate in the main Czech power grid cannot be excluded even for central-european country. This is a preliminary study. Czech: Eruptivni projevy slunev{c}ni aktivity ovlivv{n}uji bezprostv{r}edni kosmicke okoli nav{s}i Zemv{e} a postihuji prostv{r}ednictvim indukce elektrickych proudr{u} i pozemskou infrastrukturu, zejmena rozvodne sitv{e} silove elektv{r}iny. Teprve v poslednich letech byla vv{e}novana pozornost nejen hodnoceni bezprostv{r}ednich dopadr{u} silnych eruptivnich udalosti na zav{r}izeni rozvodne sitv{e}, ale take statistickemu zhodnoceni vlivu zvyv{s}ene slunev{c}ni aktivity. Ve spolupraci s v{C}EPS, a.s., jsme statisticky vyhodnotili v{c}etnost zavad na zav{r}izenich patev{r}ni rozvodne sitv{e} v{C}R v zavislosti na urovni slunev{c}ni aktivity a ukazujeme, v{z}e vliv nahlych eruptivnich udalosti na zavadovost zav{r}izeni v{c}eske rozvodne sitv{e} nelze vylouv{c}it.
rate research
Read More
Eruptive events on the Sun have an impact on the immediate surroundings of the Earth. Through induction of electric currents, they also affect Earth-bound structures such as the electric power transmission networks. Inspired by recent studies we investigate the correlation between the disturbances recorded in 12 years in the maintenance logs of the Czech electric-power distributors with the geomagnetic activity represented by the K index. We find that in case of the datasets recording the disturbances on power lines at the high and very high voltage levels and disturbances on electrical substations, there is a statistically significant increase of anomaly rates in the periods of tens of days around maxima of geomagnetic activity compared to the adjacent minima of activity. There are hints that the disturbances are more pronounced shortly after the maxima than shortly before the maxima of activity. Our results provide indirect evidence that the geomagnetically induced currents may affect the occurrence rate of anomalies registered on power-grid equipment even in the mid-latitude country in the middle of Europe. A follow-up study that includes the modelling of geomagnetically induced currents is needed to confirm our findings.
Eruptive events of solar activity often trigger abrupt variations of the geomagnetic field. Through the induction of electric currents, human infrastructures are also affected, namely the equipment of electric power transmission networks. It was shown in past studies that the rate of power-grid anomalies may increase after an exposure to strong geomagnetically induced currents. We search for a rapid response of devices in the Czech electric distribution grid to disturbed days of high geomagnetic activity. Such disturbed days are described either by the cumulative storm-time $Dst$ or $d(textit{SYM-H})/dt$ low-latitude indices mainly influenced by ring current variations, by the cumulative $AE$ high-latitude index measuring substorm-related auroral current variations, or by the cumulative $ap$ mid-latitude index measuring both ring and auroral current variations. We use superposed epoch analysis to identify possible increases of anomaly rates during and after such disturbed days. We show that in the case of abundant series of anomalies on power lines, the anomaly rate increases significantly immediately (within 1 day) after the onset of geomagnetic storms. In the case of transformers, the increase of the anomaly rate is generally delayed by 2--3 days. We also find that transformers and some electric substations seem to be sensitive to a prolonged exposure to substorms, with a delayed increase of anomalies. Overall, we show that in the 5-day period following the commencement of geomagnetic activity there is an approximately 5--10% increase in the recorded anomalies in the Czech power grid and thus this fraction of anomalies is probably related to an exposure to GICs.
We present the first release of the Czech Variable star catalogue that currently contains 1228 stars whose variability was discovered by 60 Czech observers. The catalogue contains confirmed variable stars of various types, but also candidates. We give precise coordinates, cross identification with other catalogues, information about constellation, variability type, brightness, light elements, name of the discoverer and year of discovery. In eighty-eight percent of stars the variability type is estimated, for more than 60 % of the stars the light ephemerides are given.
Power grid frequency control is a demanding task requiring expensive idle power plants to adapt the supply to the fluctuating demand. An alternative approach is controlling the demand side in such a way that certain appliances modify their operation to adapt to the power availability. This is specially important to achieve a high penetration of renewable energy sources. A number of methods to manage the demand side have been proposed. In this work we focus on dynamic demand control (DDC), where smart appliances can delay their switchings depending on the frequency of the system. We introduce a simple model to study the effects of DDC on the frequency of the power grid. The model includes the power plant equations, a stochastic model for the demand that reproduces, adjusting a single parameter, the statistical properties of frequency fluctuations measured experimentally, and a generic DDC protocol. We find that DDC can reduce small and medium size fluctuations but it can also increase the probability of observing large frequency peaks due to the necessity of recovering pending task. We also conclude that a deployment of DDC around 30-40% already allows a significant reduction of the fluctuations while keeping the number of pending tasks low.
An imperative condition for the functioning of a power-grid network is that its power generators remain synchronized. Disturbances can prompt desynchronization, which is a process that has been involved in large power outages. Here we derive a condition under which the desired synchronous state of a power grid is stable, and use this condition to identify tunable parameters of the generators that are determinants of spontaneous synchronization. Our analysis gives rise to an approach to specify parameter assignments that can enhance synchronization of any given network, which we demonstrate for a selection of both test systems and real power grids. Because our results concern spontaneous synchronization, they are relevant both for reducing dependence on conventional control devices, thus offering an additional layer of protection given that most power outages involve equipment or operational errors, and for contributing to the development of smart grids that can recover from failures in real time.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
