Due to the presence of a power electronic converter, the doubly fed induction generator (DFIG)-based wind generators are isolated from grid frequency variations, which will impose significant burden on conventional generators to regulate frequency in a hybrid remote area power supply (RAPS) system. Thus, participation of wind generators in frequency control is increasingly demanded. In this paper, a primary frequency response strategy is proposed for the DFIG to regulate the RAPS system frequency. A droop control loop without conventionally used high-pass filter is integrated to generate the torque reference for the DFIG to provide primary frequency response, and a supplementary control loop is proposed to enhance the primary frequency response with torque feedback control. Furthermore, the suggested suboptimal power point tracking strategy is capable of reserving wind power to improve the frequency response. The proposed strategy enables DFIG to participate in RAPS system frequency regulation while alleviating high rate of change of power and thus stress on the diesel generators under highly variable load demand. The effectiveness of the proposed strategy is validated through simulations.

Frequency support from renewable power generators is critical requirement to ensure the frequency stability of remote area pow-er supply (RAPS) systems with high penetration of renewable power generation. However, traditional control strategies and the stochastic nature of wind resource constrain wind energy conver-sion system (WECS) such as permanent magnet synchronous generator (PMSG) from participating in frequency regulation. This work proposes to integrate hybrid energy storage including ultracapacitors (UCs) and lead-acid batteries (LABs) into a PMSG to provide frequency support. The UCs deal with fast changing frequency by emulating conventional inertial response, whereas the LABs mimic automatic governor response (i.e., pri-mary frequency response). The mechanical power reserved in wind turbine using suboptimal maximum power point tracking (SOPPT) strategy is utilized to restore system frequency (i.e., sec-ondary frequency response). Moreover, supplementary control strategies are proposed to enable the UCs and LABs to assist primary frequency response and secondary frequency response respectively. Simulation study and experimental test are carried out to validate the effectiveness of frequency response provided by the multilevel energy storage. The multilevel energy storage solution can effectively regulate RAPS system frequency while avoiding abrupt and frequent charging/discharging of the LABs and significant mechanical/electromagnetic stress on the WECS.

Conventional generators in wind-diesel hybrid remote-area power supply (RAPS) systems are likely to be heavily stressed during frequency disturbances due to poor frequency response of power electronic interfaced wind energy conversion systems (WECSs). Hence, it is imperative for the WECS to provide frequency support during frequency excursions. However, existing frequency control strategies are slow and will also impose severe mechanical/electromagnetic stress on WECSs. In this paper, frequency response strategies for the PMSG-based WECS are explored, and an enhanced frequency response strategy is investigated to regulate the RAPS system frequency jointly with the integrated ultracapacitors. The proposed short-term frequency response strategy utilizes a virtual inertial technique along with the supplementary droop control. Suboptimal power-point-tracking is also implemented at the PMSG to improve the active power reserve. The enhanced frequency response strategy can regulate the RAPS system frequency while alleviating high rate-of-change-of-power, and thus stresses on both the conventional generator and PMSG under frequency disturbances. Proposed control strategies are validated by both simulations and experiments.

Semiconductor devices in power electronic converters of the doubly-fed induction generator (DFIG) are susceptible to significant junction temperature variations when operating around synchronous speed, thereby reducing the lifetime of the converters. This is due to the fact that the frequency of the rotor current in a DFIG is determined by the stator flux frequency and rotor speed, and hence will lead to low rotor current frequency when operating closer to the synchronous speed, and ultimately result in significant thermal stress on semiconductor devices. In this paper, a multimode operation control strategy is proposed for the DFIG to prevent operating around the synchronous speed (within a predefined deadband); thus, the proposed control strategy can avoid the thermal stress problem. The proposed strategy engages the existing crowbar scheme for DFIG-based wind energy conversion system to intentionally alter the operating mode of the generator between DFIG and induction generator (IG). Smooth transition between the two operating modes can be achieved with the supplementary control strategies. Unity power factor can also be maintained in both operating modes by using the grid side converter as a static synchronous compensator (STATCOM) to fulfill the reactive power requirement of the DFIG in IG mode.

The increasing uncertainty of distributed energy resources (DERs) challenges the secure and resilient operation of low-voltage distribution networks (LVDNs). Flexible interconnection via power-electronic devices enables controllable links among LVDAs, supporting capacity expansion, reliability, load balancing, and renewable integration. This paper proposes a two-stage robust optimization framework for flexible interconnection planning in LVDNs. The first stage determines investment decisions on siting and sizing of interconnection lines, while the second stage schedules short-term operations under worst-case wind, solar, and load uncertainties. The bi-level problem is reformulated into a master–subproblem structure and solved using a column-and-constraint generation (CCG) algorithm combined with a distributed iterative method. Case studies on typical scenarios and a modified IEEE 33-bus system show that the proposed approach mitigates overloads and cross-area imbalances, improves voltage stability, and maintains high DER utilization. Although the robust plan incurs slightly higher costs, its advantages in reliability and renewable accommodation confirm its practical value for uncertainty-aware interconnection planning in future LVDNs. Case studies on typical scenarios and a modified IEEE 33-bus system demonstrate that under the highest uncertainty the proposed method reduces the voltage fluctuation index from 0.0093 to 0.0079, lowers the autonomy index from 0.0075 to 0.0019, and eliminates all overload events compared with stochastic planning. Even under the most adverse conditions, DER utilization remains above 84%. Although the robust plan increases daily operating costs by about $70, this moderate premium yields significant gains in reliability and renewable accommodation. In addition, the decomposition-based algorithm converges within only 39 s, confirming the practical efficiency of the proposed framework for uncertainty-aware interconnection planning in future LVDNs.