Fast approach to detect generator loss of excitation based on reactive power variation

Fast and reliable index to protect the synchronous generators against loss of field incidence

“…Therefore, the merits of the proposed LOFPS of this paper can be summarised as follows: First and foremost, as demonstrated in the simulation studies, the proposed LOFPS detects all events without any wrong detection, while the impedance‐based schemes and proposed LOFPS in [10–12, 14, 21] may have mal‐operation during some events. As proved by simulation studies, the introduced LOFPS reveals all LOF and PSD events in just 200 ms, which is much smaller than the operation time of the impedance‐based schemes as well as the introduced LOFPS in [12, 13, 19, 24]. Unlike the suggested LOFPSs in [17, 18] that need some sensors and additional devices for implementation, the proposed LOFPS only uses the existed measurement devices at the SG output (e.g.…”

“…All these impedance‐based LOFPSs may mal‐operate under some PSD events. The proposed LOFPS in [12] utilised reactive power parameter for the detection of both LOF/PSD events. The main defect of this parameter is the wrong detection during the operation of the SG at the unit or near unity power factor.…”

Performance Assessment of Some Practical Loss of Excitation Detection Schemes Employing a Realistic Model

“…Numerous LOE protection schemes have been presented in the literature during the last few decades [5][6][7][8][9][10][11][12][13], while some of the recently published ones are as follows:…”

“…Setting-free schemes [7,8]; this category of schemes utilizes the time derivations of some generator parameters along with a predefined time delay, as the relay detection time. For example, the presented approach in [7] uses the time derivative of calculated resistance (dR/dt) in the generator terminal to diagnose LOE occurrences.…”

“…For example, the presented approach in [7] uses the time derivative of calculated resistance (dR/dt) in the generator terminal to diagnose LOE occurrences. Although these schemes [7][8][9] are setting-free, they are unable to detect all types of LOE incidents, particularly those ones caused by open circuit events in the excitation circuit [5,6]. • Flux-based approaches [9][10][11][12][13]; these techniques either estimate the field flux participation of the rotor winding through measuring of some output quantities of the generator [9][10][11], or employ sensors to monitor the air-gap flux of the generator [12,13].…”