With the increasing demand for electrical reliability, power grid companies often need to operate urban underground cable systems at flexible ratings during planned or emergency events, but the risk of failure caused by such loading operations has not yet been quantified. Based on this, this paper proposes a reliability assessment method for underground cables based on dual sequence Monte Carlo simulation, which can consider the cumulative risk impact caused by electrical faults and insulation aging of underground cables during emergency events. Firstly, the integration of the electrical and thermal design characteristics of the integrated underground cable system within the overall network reliability framework was introduced. A dual sequence Monte Carlo simulation loop was used to evaluate the performance of the cable and network while considering the thermal aging effects of emergency loads on the cable. Then, the proposed method is applied to improve the IEEE 14 bus network by introducing cable design risk factor α and aging risk acceptance factor β to achieve flexibility and operational risk under long-term and short-term high-load emergency rating scenarios. Finally, the research results of the IEEE 14 bus network show that the expected unserved energy of scenario 1 is 30.15 MWh/year, which is 59% lower than the basic scenario of 73.34 MWh/year. The expected network failure frequency remains almost unchanged. Scenario 2 and scenario 3 show a decrease in the gain of network performance due to emergency-rated operation after using α and β, demonstrating the accuracy of the proposed method in cable reliability assessment.

The partial discharge (PD) analysis method has remained one of the key technologies for cable condition assessment to diagnose cable operation state. In this paper, two power cable status evaluation methods are proposed based on electrical tree growth and data association rules, respectively. First, in the field of molecular thermodynamics, based on the law of energy conservation of electrical tree growth, this paper studies the relationship between PD signals in cable insulation and the length of the electrical tree. By using the length of electrical tree growth to calculate the probability of PD failure of cables, a cable state assessment method based on electrical tree growth is proposed. Second, for power cable status evaluation, the strong concealment characteristics of cables result in a long power supply recovery time and a serious threat to power supply reliability. Therefore, a group of comprehensive cable status parameters are set by analyzing the status parameters based on data association rules. The comprehensive state of power cables is divided into four elements, and the weight coefficients of cable states are calculated based on data association rule methods. Finally, the simulation results verify the effectiveness and accuracy for the two different power cable status evaluation methods.

The journal retracts the article titled “Power Cable Status Evaluation Method Based on Electrical Tree Growth and Data Association Rules”