The installed capacity of distributed generation (DG) based on renewable energy sources has increased continuously in power systems, and its market-oriented transaction is imperative. However, traditional transaction management based on centralized organizations has many disadvantages, such as high operation cost, low transparency, and potential risk of transaction data modification. Therefore, a decentralized electricity transaction mode for microgrids is proposed in this study based on blockchain and continuous double auction (CDA) mechanism. A buyer and seller initially complete the transaction matching in the CDA market. In view of the frequent price fluctuation in the CDA market, an adaptive aggressiveness strategy is used to adjust the quotation timely according to market changes. DG and consumer exchange digital certificate of power and expenditure on the blockchain system and the interests of consumers are then guaranteed by multi-signature when DG cannot generate power due to failure or other reasons. The digital certification of electricity assets is replaced by the sequence number with specific tags in the transaction script, and the size of digital certification can be adjusted according to transaction energy quantity. Finally, the feasibility of market mechanism through specific microgrid case and settlement process is also provided.

This paper proposes an electric load demand model of the 5th generation (5G) base station (BS) in a distribution system based on data flow analysis. First, the electric load model of a 5G BS is developed according to its components and their characteristics. Second, critical factors of the power consumption of 5G BS, including area, data flow with uncertainty number of activated terminals and data usage of the terminal, are discussed. A statistical model of the number of activated terminals and data usage of the terminal are established using a probability distribution, and Monte Carlo sampling is used to handle the uncertainties. Then, the model is extended for multiple terminal connections. A case study is conducted to analyze the impact of the critical factors on the load of 5G BS and the influence of 5G BSs load on the other loads in three typical areas. Numerical results demonstrate that the proposed model is effective and can be employed as an accurate representation of the 5G BS load profile for the analysis of load characteristics. Case studies also show that the 5G BS loads have diverse impact on different typical areas in a distribution system.

The use of bipolar direct current (DC) distribution systems introduces the possibility of unbalanced voltage (current). This situation increases the voltage deviations and power losses at each node owing to the presence of a neutral line current. This study proposes a method that mitigates the unbalanced voltage caused by constant power loads (CPLs) by DC electric springs (DC—ESs). A linearized model is used in the small-signal analysis of CPLs. On this basis, the coupling relationship between positive and negative pole voltages is analyzed. After DC—ESs are introduced, the positive and negative pole voltages and DC—ES output voltages are found to be closely related, thereby increasing the complexity of the control system. Therefore, a feedforward decoupling control block diagram is introduced on the basis of the small-signal model analysis of DC—ESs in a single node of the bipolar DC system. The control system is simplified, and different control loops can be independently controlled. Thus, the rapidity and anti-interference performance of the control system are greatly enhanced. Simulation and experimental results of the unbalanced voltage suppression in the bipolar DC system are used to verify the effectiveness of the proposed scheme.

In dc microgrid, the cascaded dc system has been extensively employed. However, the negative impedance characteristics of the converter may induce system instability. This article proposes an optimized parallel virtual resistance (PVR) based active damping control to improve the stability of the cascade dc system in the dc microgrid. The advantage of this method is that it not only meets the closed-loop dynamic performance of the source converter (SC), but also meets the stability requirements of matching the input impedance of the load converter. The stability range of PVR under full load and its influence on the output impedance of SC in cascade system are determined. Additionally, a large-signal model is constructed by using state-space averaging method to investigate the open-loop stability in the cascaded dc system. The suggested control stability requirements are investigated by using the Lyapunov indirect approach, and a matching PVR is then adopted to ensure system stability. Finally, the performance of the control strategy is verified by establishing a MATLAB simulation and experiment platform.

The power system experiences a significant increase in its flexibility in recent years, along with the increase in renewable energy penetration. Implementing the flexibility retrofit of thermal power units (TPUs) is an effective way to enhance power system flexibility. However, the conventional ramp rate constraint cannot reveal the ramping characteristics of TPUs during deep peak regulation after the retrofit. In this paper, to establish a constraint that is more consistent with the engineering practice, the relationship between ramping capability and unit load of TPUs is firstly analyzed, based on the field test data of a TPU in China. Then, a ladder-type ramp rate of the TPU is proposed before a unified expression for the constraint is derived for the first time. When a specific dispatch time scale is satisfied, an equivalent expression for this constraint is also derived. Finally, the dimensionality of the binary variables in ladder-type ramp rate constraint is discussed, and the effectiveness of the ladder-type ramp rate constraint of the TPU is initially verified, with the actual 1-year operating data of two TPUs of a power plant in Dalian, Liaoning Province, China.

The precise identification of fault locations in multiterminal dc (MTDC) transmission systems using traveling waves (TWs) is imperative for ensuring the secure and stable operation of power systems. The presence of wave impedance discontinuity in overhead-cable hybrid transmission lines (OCHTLs) causes significant changes in TW velocity. Traditional TW-based fault location methods struggle to adapt to these changes. This article introduces an innovative fault location approach tailored for OCHTL, with the primary aim of enhancing fault-ranging accuracy. Initially, a typical OCHTL equivalent model is established, and the propagation characteristics of the OCHTLs’ fault voltage TW (VTW) are analyzed. The variational mode decomposition-Teager energy operator (VMD-TEO) algorithm is then employed to determine the arrival time of the VTW wavefront. To optimize VMD parameters, the Kullback–Leibler (K–L) divergence method is applied, addressing modal aliasing. Additionally, we explore TW velocity attenuation characteristics across segments and introduce a frequency-modified algorithm for faulty segment identification. A high-precision fault location algorithm is then proposed based on two-terminal information, and its robustness and accuracy are validated through simulations using a PSCAD-built MTDC system with OCHTLs.