In this paper, a novel resistance network node potential measurement technique based on 16-channel cycle method is presented, and a grounding grids corrosion diagnosis measurement system with 16 channels is built from this method. Through this measurement system, 1,680 valid potential data and 1,560 effective branch voltage data can be collected in one measurement by only 16 accessible node downleads on the grounding grid. The stability error of the excitation current source is less than 0.15%, and the error of the applicable acquisition data is about 1% according to system data tests. Built on the measurements, an underdetermined sensitivity equation for solving the increasing multiple of branch resistance is put in place to determine the corrosion status of grounding grids. The experimental results show that the plenty of data is necessary when solving the underdetermined equation and also show that the system is under a high stability, high accuracy, and can comply with the requirements of corrosion diagnosis for grounding grids.
1. Dimopoulos, A., et al., "Proposal for probabilistic risk assessment in grounding systems and its application to transmission substations," IEEE Trans. Power Del., Vol. 27, No. 4, 2219-2226, Oct. 2012. doi:10.1109/TPWRD.2012.2204440
2., IEEE Guide for Safety in AC Substation Grounding, IEEE Std 80-2000, 2000.
3. Long, X., et al., "Online monitoring of substation grounding grid conditions using touch and step voltage sensors," IEEE Transactions on Smart Grid, Vol. 3, No. 2, 761-769, Jun. 2012. doi:10.1109/TSG.2011.2175456
4. Sverak, J. G., W. Wang, Y. Gervais, X. D. Do, and D. Mukedkar, "A probabilistic method for the design of power grounding systems," IEEE Trans. Power Del., Vol. 7, No. 3, 1196-1206, Jul. 1992. doi:10.1109/61.141831
5. Sverak, J. G., W. K. Dick, T. H. Dodds, and R. H. Heppe, "Safe substation grounding-part I," IEEE Transactions on Power Apparatus and Systems, Vol. 100, 4281-4290, Sep. 1981. doi:10.1109/TPAS.1981.316934
6. Celli, G., E. Ghiani, and F. Pilo, "Behaviour of grounding systems: A quasi-static EMTP model and its validation," Electric Power Systems Research, Vol. 85, 24-29, Apr. 2012. doi:10.1016/j.epsr.2011.07.004
7. Heimbach, M. and L. D. Grcev, "Grounding system analysis in transients programs applying electromagnetic field approach," IEEE Trans. Power Del., Vol. 12, No. 1, 186-193, Jan. 1997. doi:10.1109/61.568240
8. Dommel, H. W., "Digital computer solution of electromagnetic transient in single and multiple networks," IEEE Trans. Power App. Syst., Vol. 88, No. 4, 388-399, Apr. 1969. doi:10.1109/TPAS.1969.292459
9. Otero, A. F., J. Cidras, and J. L. del Alamo, "Frequency-dependent grounding system calculation by means of a conventional nodal analysis technique," IEEE Trans. Power Del., Vol. 14, No. 3, 873-878, Jul. 1999. doi:10.1109/61.772327
10. Lawson, V. R., "Problems and detection of line anchor and substation ground grid corrosion," IEEE Transactions on Industry Applications, Vol. 24, No. 1, 25-32, Jan.-Feb. 1988. doi:10.1109/28.87245
11. Patel, S., "A complete field analysis of substation ground grid by applying continuous low voltage fault," IEEE Trans. Power App. Syst., Vol. 104, No. 8, 2238-2243, Aug. 1985. doi:10.1109/TPAS.1985.318804
12. Liu, J., et al., "Grounding grids corrosion diagnosis using a block dividing approach," High Voltage Engineering, Vol. 37, 1194-1202, May 2011 (in Chinese).
13. Ni, Y. F., et al., "Splitting method for grounding grids corrosion diagnosis using a block dividing approach," High Voltage Engineering, Vol. 37, 2250-2260, Sep. 2011 (in Chinese).
14. Dawalibi, F., "Electromagnetic fields generated by overhead and buried short conductors part 2 - ground networks," IEEE Trans. Power Delivery, Vol. 1, 112-119, Oct. 1986.
15. Yan, M., G. G. Karady, and S. Kucuksari, "Testing continuity of grounding grid using the AC current injection method," IEEE Power and Energy Society General Meeting, 1-6, 2010.
16. He, W., et al., "Computation method of magnetic field inverse problem on grounding grids fault diagnosis," Journal of Chongqing University, Vol. 35, 80-85, Sep. 2012 (in Chinese).
17. Huang, L. and D. G. Kasten, "Modeling of ground grid and metallic structure currents in high voltage a.c. substations for the computation of electromagnetic fields," Electric Power Systems Research, Vol. 59, 31-37, Mar. 2001.
18. Zhang, B., et al., "Diagnosis of breaks in substation’s grounding grid by using the electromagnetic method," IEEE Trans. Magn., Vol. 38, 473-476, Mar. 2002. doi:10.1109/20.996125
19. Liu, Y., X. Cui, and Z. Zhao, "Design and application of exciting power for substation grounding grids tests system based on impedance transformation technology," Proceedings of the CSEE, Vol. 28, 18-23, Oct. 2008 (in Chinese).
20. Cheng, H., et al., "Grounding grids corrosion diagnosis automation test system and its key techniques," High Voltage Engineering, Vol. 35, 2989-2994, Dec. 2009 (in Chinese).
21. Texas Instruments Inc. ADS1241E datasheet, , [Online], Available: http://www.ti.com/product/ads1241.
23. Zeng, J., S. Lin, and Z. Xu, "Sparse solution of underdetermined linear equations via adaptively iterative thresholding," Signal Processing, Vol. 97, 152-161, Apr. 2014. doi:10.1016/j.sigpro.2013.10.031