Short-term load forecasting (STLF) plays a significant role in the operation of electricity trading markets. Considering the growing concern of data privacy, federated learning (FL) is increasingly adopted to train STLF models for utility companies (UCs) in recent research. Inspiringly, in wholesale markets, as it is not realistic for power plants (PPs) to access UCs' data directly, FL is definitely a feasible solution of obtaining an accurate STLF model for PPs. However, due to FL's distributed nature and intense competition among UCs, defects increasingly occur and lead to poor performance of the STLF model, indicating that simply adopting FL is not enough. In this paper, we propose a DRL-assisted FL approach, DEfect-AwaRe federated soft actor-critic (DearFSAC), to robustly train an accurate STLF model for PPs to forecast precise short-term utility electricity demand. Firstly. we design a STLF model based on long short-term memory (LSTM) using just historical load data and time data. Furthermore, considering the uncertainty of defects occurrence, a deep reinforcement learning (DRL) algorithm is adopted to assist FL by alleviating model degradation caused by defects. In addition, for faster convergence of FL training, an auto-encoder is designed for both dimension reduction and quality evaluation of uploaded models. In the simulations, we validate our approach on real data of Helsinki's UCs in 2019. The results show that DearFSAC outperforms all the other approaches no matter if defects occur or not.

Unfortunately, conventional approaches pay little attention to most defects [Fung In federated learning (FL), model aggregation has et al., 2018]. Therefore, an efficient approach to alleviating been widely adopted for data privacy. In recent performance degradation caused by defective local models is years, assigning different weights to local models strongly needed for FL. Existing researches on blockchainbased has been used to alleviate the FL performance FL have defined the concept of reputation, which manifests degradation caused by differences between local the reliability of each local model [Kang et al., 2019] datasets. However, when various defects make the [Kang et al., 2020]. Similarly, we evaluate the model quality FL process unreliable, most existing FL approaches to measure how trustworthy a local model is. After learning expose weak robustness. In this paper, we propose about the quality of each local model, we are motivated to design the DEfect-AwaRe federated soft actor-critic a deep neural network (DNN) to assign optimal weights (DearFSAC) to dynamically assign weights to local to local models, so that the global model can maintain a considerable models to improve the robustness of FL. The deep performance no matter if there exist defects or not.