## 1 Introduction
Previous studies on dust and soiling were performed under various experimental conditions and module types [15; 16; 17; 18]. A previous research examined the correlation between dust and wind velocity by making an experimental device to quantify the effects of wind velocity and dust [19], and there was also research on the characteristics of dust particles, such as the density, size, volume, and the specific weight [20]. In addition, a prior study compared the efficiencies depending on the presence or absence of cleaning, using long-term measured data after exposing the module to ambient air [18]. The results of outdoor experiments showed that 40% of the maximum module efficiency was lost due to dust. A study conducted through exposure to ambient air without artificially changing the experimental conditions suggested that the effects of dust were influenced significantly by regional characteristics. On the other hand, there has been a lack of research on the performance degradation related to the power conditioning system (PCS). Since the power generated from the PV array is DC, it must be converted to AC power in order to supply electric power to the electric load equipment, or to connect with the grid. This role is performed in the PCS. In addition, it should have the maximum power point tracking (MPPT) control function so that the output of the PV array can always generate at the maximum power point. Since it operates in conjunction with the grid, it protects the PCS from system accidents, it should have several protective functions to protect the system. For this reason, it is called the power conditioner or PCS, as it is different from a general purpose inverter. Previous studies have attempted to predict the PCS temperature increase related to the performance of the PCS [21], select the optimized capacity of PCS using measured data [22], and assess MPPT controls, one of the functions of PCS [23; 24]. In previous studies, various loss factors were investigated, but there has been no research on the various installation conditions (azimuth angle and inclined angle) in the same system, so there are limitations on making a comparison among the performance loss factors according to the installation conditions. In addition, there is a paucity of research on the correlations among the PCS stands by loss, PCS capacity, and the array capacity. The main purpose of this paper is to evaluate the power generation performance loss factors that can occur in BIPV and PV systems by installation conditions. The effect of the power generation performance loss factors varies, depending on the installation conditions. For this reason, this paper evaluates the effect using actual monitoring data of a BIPV system composed of various installation conditions (horizontal, south-inclined, south-vertical, west-vertical). Among various power generation performance loss factors, this paper analyzed DC-AC conversion loss caused by a capacity mismatch of PV arrays and PCS that can occur in the system design, module temperature, dust and soiling, and PCS standby loss during operation. Following this introduction, Section 2 presents a method for analyzing the effects of power generation performance and generation performance loss factors, and Section 3 introduces the BIPV performance test facility analyzed in this study. Sections 4 and 5 present the results of the power generation performance analysis and the analysis of the effect of each performance loss factors. Finally, Section 6 outlines the conclusion of the paper and discusses the results.