The converter module requires reactive power from the ac bus in approximate proportion to the active power being delivered to the utility network. This reactive power is supplied by static capacitors, harmonic filters and synchronous condensers. Performance during the semi-annual eclipse periods can be made largely automatic. As RF power decreases during the partial eclipse period the converter, through its constant resistance load characteristics, will track the rectenna output and provide available power. The principle problem during these eclipse periods will be power dispatch in the ac system to preserve load and frequency. A mitigating factor will be that the power loss occurs at night when the ac system is most able to cope with it. SPS Operating Characteristics Currently accepted response characteristics for electric utility system generating plants and measures of utility system reliability have been the basis for the integration of SPS power with electric utility systems. Two of the power control methods, 2 and 4, described in Table 2 were deemed practicable and acceptable by utility system criteria. The response times and power control range for these two methods are compared with conventional generating unit characteristics in Figure 1. It is seen that the SPS response in both cases is better than that of conventional generation. The SPS is unlike conventional generation in that it has no mechanical inertia and hence appears as a negative load to the system. Control of the incident power will be at the satellite antenna via communications link and this control loop, involving transmission of control signals through space, is the nearest analog of governor control of a conventional generation source. The study of impacts on system reliability adding SPS generation to electric utility systems was based on a reliability model for SPS as shown in Figure 2. These probability plots were developed using the information in Table 1 combined with a failure analysis of the rectenna system. These curves, however, are too complex to be used directly in current utility system reliability planning models. A simplified 5-state outage model was used in a parametric approach to determine the impact of SPS power on utility system reserve levels for various amounts of SPS penetration. The results of this investigation are shown in Figure 3. Conclusions The results indicate that if RF beam control is an acceptable method for power control, and that the site distribution of SPS rectennas do not cause a very high local penetration (40-50%), SPS may be integrated into electric utility system with a few negative impacts. Increased regulating duty on the conventional generation, and a potential impact on system reliability for SPS penetration in excess of about 25% appear to be two areas of concern. Assessment of more detailed models and advanced design parameters for the SPS system must be done before it would be possible to investigate the SPS/Utility System integration in more detail.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==