Enhance and assess wide area probing responses in low level probing tests

Damping controller such as wide area PSS (WAPSS) employed on the excitation system is effective in interarea oscillation control. To well design a WAPSS, an accurate dynamic model should be established. With the development of wide area measurement system (WAMS) and low level probing tests, it is feasible to estimate a wide area dynamic model without large disturbance. However, as power capacity of the selected generator could be small, due to existence of ambient noise, the wide area probing response may be annihilated even the generator surfers from large disturbance. This paper presents an effective method to solve the aroused problem. Generators in the same station are combine-probed with the same signal for higher probing responses. Deviation analysis shows if parameters of the combine-probed generators are similar, the approach is feasible. A modified signal to noise ratio (SNR) is also provided to assess the probing responses. The whole work is carried out in a large complex system, China Southern Grid (CSG).