You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Integration of UPQC for Power Quality improvement in distributed generation network - a review 
Chapter Title:  II. INTEGRATION OF UPQC 
1. Abstract of Cited Paper (BIB001):  This paper describes analysis results of a combined operation of the unified power quality conditioner with the distributed generation. The proposed system consists of a series inverter, a shunt inverter, and a distributed generator connected in the dc link through a rectifier. The proposed system can compensate voltage sag and swell, voltage interruption, harmonics, and reactive power in both interconnected mode and islanding mode. The performance of proposed system was analyzed using simulations with power system computer aided design/electromagnetic transients dc analysis program, and experimental results with the hardware prototype. The proposed system can improve the power quality at the point of installation on power distribution systems or industrial power systems. 
2. Abstract of Cited Paper (BIB002):  The ability of wind generation to remain connected to the grid in the event of system faults and dynamic reactive power compensation are two aspects of grid integration, which have received particular attention. The wind driven, fixed-speed induction generator (FSIG) on its own fails to fulfil these requirements of grid integration. The application of a unified power quality conditioner (UPQC) to overcome the grid integration problems of the FSIG is investigated. The role of the UPQC in enhancing the fault ride-through capability of the generator is also investigated under both full and partial terminal voltage restoration. A realistic estimation of the rating requirements of UPQC for this type of application is carried out. A general principle is presented to choose the most practical and economical rating of the UPQC. The performance comparison of a UPQC and a static synchronous compensator to aid fault ride-through capability of a 2 MW FSIG under Irish grid code requirements has been carried out and the UPQC is found to be more economical in relation to device rating. 
3. Abstract of Cited Paper (BIB003):  The use of Dispersed or Distributed Generation (DG) has been increased in recent years to fill the gap between supply and demand of energy, as the sources of conventional power generation are depleting fast. DGs through static compensators are also used for improving the power quality of distribution systems like mitigation of voltage dips and compensation of harmonics. Shunt, series, and series-shunt type of configuration of static compensators combined with DG have been proposed in the literature. This paper presents a feasibility analysis of DGSC-UPQC (Distributed Generation based Static Compensator as Unified Power Quality Conditioner), a series-shunt type of static compensator with DG. The analysis has been carried from technical and economical aspects when the device i.e. DGSC-UPQC is used for compensation of unbalance in source voltages and load currents and power factor improvement. Simulation results show the capability of the DGSC-UPQC to compensate the unbalance in source voltages and load currents satisfactorily.

Literature Review:
Recent reports BIB002 BIB001    BIB004 BIB003  show that significant research and development has been carried out on the application of UPQC to DG integrated network. As the UPQC can compensate for almost all existing PQ problems in the transmission and distribution grid, placement of a UPQC in the distributed generation network can be multipurpose. As a part of integration of UPQC in DG systems, research has been done on the following two techniques: DC-Linked and Separated DG-UPQC systems.