基于脉动参数热路模型的架空线路动态增容风险评估

架空输电线路动态增容的热路模型对环境气象依赖性小,但忽略了环境热阻脉动,故当线路温度波动时,增容风险评估可能出现偏差。为此,通过引入平均热阻和脉动热阻参数,提出了一种计及参数脉动特性的线路增容热路模型。基于参数辨识和马尔可夫链方法,对模型参数及其随机特性进行了确定。利用架空导线温升实验平台,对所提模型有效性进行了验证。实验与计算结果表明:当导线温度存在波动时,参数辨识方法得到的平均热阻精度高于传统计算方法;马尔可夫链能够得到脉动热阻的统计规律,并生成随机特性相似的模拟序列;得到热阻参数后,所述模型能够描述导线温度受环境气象影响而产生的波动,并以概率形式对载流量进行有效估计,将增容风险控制在合理范围内,为电力系统运行和调度提供必要依据。

Risk Assessment of Dynamic Overhead Lines Rating Based on Thermal Circuit Model Considering Pulsating Characteristic of Parameters

The thermal circuit model for dynamic overhead lines rating has the advantage of little dependence on ambient meteorology. But for the neglect of pulsating characteristics of thermal resistance, this model will lead to large errors in risk assessment for dynamic rating when the conductor temperature fluctuates. This paper proposes a new thermal circuit model for dynamic overhead lines rating which considers pulsating characteristics of parameters by introducing the parameters of average thermal resistance and pulsating thermal resistance. The model parameters and their stochastic characteristics are determined by parameter identification and Markov chain method. A temperature rise experiment platform for current-carrying conductor is used for model verification. The experiment and calculation results show that the precision of average thermal resistance determined by parameter identification is higher than that determined by the traditional method if the conductor temperature fluctuates. The statistical law of pulsating thermal resistance can be obtained and a simulated sequence which has a similar statistical law can be generated by Markov chain. After that, the proposed model can reflect conductor temperature fluctuation caused by ambient meteorology and estimate ampacity in the form of probability. Using this model, the risk of dynamic overhead lines rating is controlled in a rational range and the basis for power system operation and scheduling is proved.