Yutian Zhou

Assessing the impacts of extreme temperatures and water availability on the resilience of the GB power system

Extreme weather events or more in general changing environmental conditions (for instance due to climate change) might have significant impacts on future power systems, threatening their resilient operation. In this context, this paper provides a quantitative analysis of the temperature and water availability effects on power system resilience. Differently from most existing work that only addresses the impact on individual power plants and independently of the context, a system level assessment is conducted here through a time-series model that specifically considers the temperature sensitivity and the impact of water availability on the cooling systems of all conventional thermal power plants, as well as the temperature sensitivity of line capacities and of electrical demand throughout the network. Sequential Monte Carlo Simulation (SMCS) is used to capture the stochastic impacts of such phenomena and derive relevant impact metrics. The model is demonstrated on a 29-bus reduced representation of the Great Britain (GB) transmission network. Several future scenarios for future generation and demand are formulated with different corresponding weather parameter. The results help recognize the vulnerability and resilience of future GB power systems to extreme weather events under different conditions.

Generation adequacy in wind rich power systems: Comparison of analytical and simulation approaches

The analytical and simulation approaches used for generation adequacy assessment are reviewed in this paper in the context of large-scale wind penetration. The analytical approach applied by the UK system regulator and sequential Monte Carlo simulation (MCS) are compared based on a realistic model of the UK power system. It is found that the analytical approach yields a higher risk of security of supply compared to sequential MCS approach. This is due to the fact that the analytical approach fails to take into account the inherently chronological nature of wind power. A further contribution of this paper is the estimate of the duration and severity of single capacity shortfall provided via sequential MCS. This is essential to future networks in which alternative resources (mainly demand response and storage) can be deployed as proxies for capacity. Moreover, high impact and low probability events are captured properly through sequential MCS. A key conclusion of this paper is that sequential MCS should be applied to estimate generation adequacy as it provides more realistic results of the various indicators.

Analyzing the resilience and flexibility of power systems to future demand and supply scenarios

A systematic resilience and flexibility analysis of future power systems to address the impacts of climate change and Renewable Energy penetration is becoming increasingly important, as it is expected to have a great effect on the demand and supply portfolios. Depending on the intrinsic characteristics of each power system, different aspects have to be considered in the analysis since this cannot be universal for all power systems. To highlight this, the paper presents two different case studies pertaining to the Great Britain and Cyprus networks respectively. Firstly, the resilience of the Great Britain transmission network to future demand and supply scenarios (2020, 2030 and 2050) is evaluated using a reduced version of the current Great Britain transmission network. Subsequently, the future flexibility requirements of the isolated network of Cyprus are appropriately benchmarked against future energy mix scenarios that involve conventional generation and renewable energy penetration.

System level assessment of PV and energy storage: Application to the Great Britain power system

The main aim of this work is to add to the debate about the potential roles of photovoltaics (PV) and storage in the future GB power system. To do so, this paper has developed models to assess the system level performance of coordinated PV and storage in terms of the provision of system capacity and operational implications. More specifically, on the one hand, in the days with system critical peak demands, a centralised control strategy is considered to use storage to shift the energy generated by PV to supply system demand at peak times; on the other hand, in the rest of the year, storage is then controlled in a distributed way to primarily maximise the self-consumption of solar energy and secondly minimise the instantaneous feed-in power from PV panels. Afterwards, the contribution to system capacity from coordinated PV and storage is evaluated by using a capacity credit assessment, while the operational implications are analysed by focusing on the overall system operational cost and the amount of PV generation that needs to be curtailed. In summary, according to the assessments, it has been found that in the case of GB, the proposed coordinated control of PV and storage can, but to a limited extent, contribute to the provision of system capacity, reduce system operational cost, and increase the utilisation of solar energy.

Security of supply implication of residential photovoltaic panels in low voltage network

Residential photovoltaic (PV) panels are playing an essential role in the delivery of sustainable power systems. Major research has addressed the operation issues induced by PV panels, such as voltage problems. However, there is a lack of study on the security of supply implication of residential PV panels on the low voltage network. Hence, this paper introduces a framework of estimating the impact of using PV panels on the reliability indices practiced by the Distribution Network Operators in the UK. A self-supply scheme is proposed to employ residential PV panels by customers under the feeder-fault condition. A sequential Monte Carlo based methodology is used to estimate the reliability indices. A real UK distribution feeder is used to demonstrate the fundamental effects of using PV panels on a real low voltage network. It is found that using PV panels reduces the overall duration and unserved energy of interruptions during a year; however, due to the intermittency of PV generation during the period of resolving the feeder-fault, the annual frequency of interruptions is increased. The monthly study is also conducted as complement for the annual results to show the seasonal impacts of using PV panels on customer reliability.

The impact of dynamic generation prices on transmission capacity planning under competitive electricity market

This paper explores the impact of dynamic generation prices (DGP) on transmission network capacity planning. A model based on the framework of DC optimal power flow is proposed to solve the transmission planning problem considering DGP, as well as the network security constraints. The transmission planning problem is formulated as a mixed-integer optimisation model with the objective of minimizing the costs of network constraints and transmission investment over several typical daily load scenarios. The methodology is illustrated with the IEEE 14-Bus test system under weak, relatively strong and strong network conditions.