An Efficient Algorithm for Partial Discharge Localization in High-Voltage Systems Using Received Signal Strength  
[PERSON]  
1 Department of Engineering & Technology, University of Huddersfield, Huddersfield HD1 3 DH, UK;  
[PERSON]  
1 Department of Engineering & Technology, University of Huddersfield, Huddersfield HD1 3 DH, UK;  
[PERSON]ESS] (H.M.); [PERSON]RESS] (L.A.G.) 1 Department of Engineering & Technology, University of Huddersfield, Huddersfield HD1 3 DH, UK;  
[PERSON]SS] (H.M.); [PERSON]RESS] (L.A.G.) 2 Department of Engineering & Technology, University of Huddersfield, Huddersfield HD1 3 DH, UK;  
[PERSON]SS] (H.M.); [PERSON]RESS] (L.A.G.) 2 Department of Engineering & Technology, University of Huddersfield, Huddersfield HD1 3 DH, UK;  
[PERSON]SS] (H.M.); [PERSON]RESS] (L.  
Issues such as manufacturing defects, poor repairs, poor quality, poor design as well as the aging processes can all lead to partial discharge [3; 5]. PD only partially bridges the electrodes that sustain the electric field and it is thus a localized discharge. The PD pulse rise time is usually very low and the pulse usually lasts for \(10 ns\)[3; 6; 7]. PD pulses have a frequency spectrum in the high frequency (HF), very-high frequency (VHF) and the ultra-high frequency (UHF) range, a large amount of which is radiated from conductors that are in the close vicinity of the PD source. PD activity mainly takes place in HV systems that include power generators, power transformers, power cables and switchgears [8]. Major sites where PD activity is heavy include cavities, joints, voids and delamination zones in HV systems [9; 10; 11]. To monitor an HV system's state, PD detection surveys are usually performed on a periodic basis. Power companies normally measure PD activity every few months. The frequency of measurements is typically twice a year or not more than once every quarter. To continuously monitor and locate a PD activity, a novel location algorithm is proposed that is based on the received signal strength (RSS). The proposed algorithm locates the PD source in an anonymous environment, i.e., there is no prior information about the source transmitted power and the path loss exponent (PLE). The distance between two sensors is estimated from measured values of the received signal and localization is performed by using the multilateration technique. The algorithm is based on the propagation equation given as Equation (1) below:  
\[P_{R}=P_{t}-10\alpha log\left(\frac{r_{i}}{r_{1}}\right) \tag{1}\]  
\(P_{R}\) is the measured signal strength by the receiving node in d\(Bm\), \(P_{t}\) is the transmitted power of the source which is unknown and again measured in d\(Bm\), \(\alpha\) is the path loss exponent which again is unknown, however it can be constrained. \(r_{i}\) and \(r_{1}\) are the \(i\)th and the first node distance from the PD source in meter. The first node is chosen as the reference node hence \(r_{1}\) represents the reference node distance from the PD source. Practically, Equation (1) remains unsolvable due to \(P_{t}\) and \(\alpha\) being unknown and this is the main challenge to be resolved to estimate the location of the unknown source. Firstly, source transmitted power is eliminated by using the ratio of distances approach which is explained in detail in Section 2. Secondly, to overcome with PLE issue, an initial value of PLE is chosen and mean spatial location is estimated from all estimated locations. The path loss exponent is then optimized within constrained limit. This is again explained in detail in Section 2. The feasibility of the algorithm was tested by estimating the location of PD source at nine different positions. Comparisons of the proposed algorithm with the ratio and search and the least squares algorithms show that the proposed algorithm offers better accuracy for at least the two field-trials that were performed. Section 1.1 describes briefly about existing algorithms for PD localization and PD signal radiation.