接地网是电力系统的重要组成部分，根据阻抗特性可判断其接地性能，但是目前还没有宽频大功率的接地阻抗特性测试装置，因此，研究针对接地网的接地装置宽频带综合测试系统具有重要的工程应用价值。 针对现有接地阻抗测量装置存在的不足，提出了一种接地装置宽频阻抗特性测试系统方案。主电路采用“交流直流变换+直流交流变换”的两级结构，其中交流直流变换实现输出电压的全范围调节，直流交流变换实现宽频大功率的输出激励信号。采用比例扩充的办法，并使用DSP产生单极性宽频SPWM，在增大了输出正弦波频率范围的同时降低了谐波。通过对LC滤波器的特性进行分析，考虑到宽频输出信号的要求，设计了两组滤波器参数，一组用于输出低频正弦波时滤除谐波，另一组用于高频谐振，从而提高整个频率范围内的波形质量。通过可编程增益放大器(PGA)与12位A/D相结合，在实现量程自动换挡的同时保证了系统宽范围的测量精度。通过引入模糊控制，有效避免了测量数据微小波动而导致的档位频繁切换现象。在进行AC/DC输出和滤波参数切换时，采用逻辑控制电路关断逆变主电路并降低其母线电压的方法确保了切换安全。基于精密整流电路实现了对输出宽频正弦波的无损整流，以便于使用平均值对系统进行反馈调节。使用自定义的数据通信格式，实现了ARM与DSP之间的信息交互。采用层级式的程序结构，以模块化方式逐层进行软件功能与状态等级的划分与编写，使结构清晰且易于维护和升级。 通过对接地装置宽频带综合测试系统的实现和实验研究，验证了所做研究成果的正确性。并在现有成果的基础之上，提出了进一步改善和提升系统性能所可以努力的方向。

Grounding grid is an important part of the power system, its grounding performance is judged by the impedance characteristics, but there is no broadband and high-power grounding impedance characteristics test device, therefore, the research on grounding device broadband integrated test system of grounding grid has an important application value of engineering. Aiming at the shortcoming of current grounding impedance measuring device, a broadband impedance characteristics test system scheme of grounding device is proposed. The "AC-DC + DC-AC" two-stage configuration is used in the main circuit, the full range adjustment of output voltage is realized by AC-DC, the broadband and high-power output excitation signal is realized by DC-AC. Using the approach of proportion extension, and the sine table is extended, The DSP is used to generate unipolar SPWM, the output range of sine wave frequency is increased and the harmonics is reduced. The LC filter characteristics were analyzed, and considering the requirement of wideband output signal , two sets of filter parameters is designed, a group is used to filtering harmonics when output low-frequency sine wave, the other group is to generate high-frequen cyresonance to improve waveform quality over the entire frequency range.The approach combining programmable gain amplifier (PGA) and 12-bit A/D is used, the measurement accuracy is insured when realize automatic shifting. The idea of fuzzy control is introduced, and the gears frequent switchover phenomenon due to minor fluctuations in the measurement data can be effectively prevented. When the AC/DC switch over and filter parameters change, the shifting safety is ensured by using logic control circuit block MOSFET driver level and reducing shift voltage. The output broadband sine wave is lossless rectified by the precision rectifier circuit to achieve system feedback regulation through using the average. The information exchange between ARM and DSP is realized by using self-defined data communication format. The hierarchical procedure structure is used, software functions and status level are divided and written layer by layer in a modular manner, its structure is clear and easy to maintain and upgrade. The grounding device broadband integration test system is realized, experiments results are in positive to verify the feasibility of the obtained research findings. And based on the existing researches, the research direction of further improving and enhancing system performance is also proposed.