MEASUREMENT AND ENHANCEMENT OF THE RESILIENCE OF POWER SYSTEMS WITH A COMBINED DIESEL AND SOLAR POWER BACKUP
Date
2019-05-31
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0001-7386-5417
Type
Thesis
Degree Level
Masters
Abstract
Power outages shut down facilities such as hospitals, shelters, and communication services. Each power system needs to be resilient to power outages. In a power system, resilience can be achieved by infrastructure hardening; smart meter (AMI), energy storage, micro grid, renewable energy and accessibility of critical components. Most critical systems, such as hospitals, have a backup power that is deiseal power generator. The resilience of such a power system refers to how a backup power can still supply the critical load or base load for such critical systems when facing to the prime power outage. This thesis studies how the resilience of such a power system can be quantitatively measured and whether a combined diesel and solar backup power can enhance the resilience of the entire power system with an affordable cost. Specifically, the hospitals in Saskatoon were taken as a study vehicle. A literature review was conducted first, which revealed that there was no satisfactory quantitative measurement available in literature for the resilience of power systems on the occasion of prime power outages.
The overall objective of this thesis was thus to develop a quantitative measure for the resilience of power systems with a backup power when facing the prime power outage. The problem is in essence about the reliability of the backup power in the event of the prime grid power is disrupted. A general measure for the resilience of the backup power system (R for short), which can be multiple types of power generators, was developed, which was dimensionless (i.e., independent of the scale of the system). The measure was proved to be reasonable to the extreme cases (i.e., R=0, R=1). The use of the proposed measurement was illustrated for two situations of the backup power: (i) the backup power being a diesel power generator only, and (ii) the backup power being a combined diesel power generator and solar panel. The situation (i) corresponds to the current situation of the backup power in the hospitals in Saskatoon. The result shows that the resilience of the RUH (royal university hospital) is the highest one (R=70.5%) among the three hospitals in Saskatoon with the other two being SCH (Saskatoon City Hospital) and SPH (Saint Paul Hospital), and the resilience of SPH is the lowest one (R=54%). This result was in agreement with the experience of the managers of the hospitals.
The economics of the combined backup power (diesel plus solar power generators) was studied with the help of a software system called SAM (system advisor model). Specifically, the power generated by and economic attributes of the solar panel of different sizes without battery storage were analyzed for the three hospitals, respectively. Note that the economic attributes are NPV (net present value) and payback time. The resilience of the combined backup power was calculated for different sizes of solar panels with the help of SAM and the proposed measure. The optimal design, namely the size of solar panel, was obtained in terms of the resilience and payback time; specifically, for the RUH, the size of solar panel is 700 KW (R of the solar panel alone is 35%; R of the combined backup power is 98%; the payback is 13.1 years, the capital cost is 1488490$), for the SPH, the size of solar panel is 500 KW (R of the solar panel alone is 25%; R of the combined backup power is 96%; the payback is 11.1 years, the capital cost is 1060390$), and for the SCH, the size of solar panel is 500 KW (R of the solar panel alone is 20%; R of the combined backup power is 94%; the payback is 10.4 years, the capital cost is $1060940). Besides, in the normal situation, the reduction of the grid power by solar power is about 7%. This research can thus conclude that the resilience of the backup power system of the hospitals in Saskatoon can be improved by adding solar panels with an acceptable cost payback time and at the same time the environmental sustainability, related to the fossil fuel power generation, can is also improved.
The primary contribution of this thesis research is the provision of a quantitative measure for the resilience of a power system including a backup power, especially with respect to the recovery stage in the event of the prime power outage. The secondary contribution is the increase of the resilience of the power system of the hospitals in Saskatoon by 25% for SPH, 35% for RUH, and 20% for SCH and the reduction of the use of the grid power by 7% for the benefit to the environmental sustainability.
Description
Keywords
resilience measurement, power system, combined backup power
Citation
Degree
Master of Science (M.Sc.)
Department
Biomedical Engineering
Program
Electrical Engineering