Grounding and ground fault protection of multiple generator installations on medium-voltage industrial and commercial power systems II. Grounding methods

Pillai, P.; Pierce, A.; Bailey, B.; Douglas, B.; Mozina, Charles J.; Normand, C.; Love, D.J.; Shipp, D.D.; Dalke, G.; Jones, James R.; Fischer, J.; Bowen, J.; Padden, Lorraine K.; Powell, L.J.; Nichols, N.; Young, R.; Stringer, N.T.

doi:10.1109/papcon.2003.1216901

Cited by 5 publications

(4 citation statements)

References 8 publications

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“…Ground faults are a major cause of stator winding damage. A ground fault in the stator winding of a synchronous generator causes the flow of current whose magnitude is dependent on the grounding method employed on the generator and also limited by the fault impedance [1]. The flow of the fault current if not interrupted often results in insulation breakdown of the stator winding and burning of lamination portions in severe cases.…”

Section: Introductionmentioning

confidence: 99%

“…Ordinary zero sequence voltage relays used for winding protection against single phase ground faults on unit connected generators cannot cover 100% of stator winding, i.e. there is a dead zone at or near the generator neutral [2] Zero sequence voltage relays can only detect faults over 90-95% of the stator winding. Typically 5% -10% of the winding portion is unprotected.…”

Section: Introductionmentioning

confidence: 99%

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Parallel Unit-Connected Generator Model for Third Harmonic Stator Ground Fault Protection

Adepoju¹,

Ogunjuyigbe²,

Brimmo³

2014

IJRET

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Conventional ground fault protection schemes can be applied for any generator terminal connection but it covers at most 95% of generator stator length. 100% protection for synchronous generator stator winding can be achieved by a combination of zero sequence and third harmonic protection schemes. The implementation of the third harmonic scheme on any generator is determined by magnitude of third harmonic voltage produced in the generator. The methods of connecting the generator terminal also influence the range of third harmonic voltage at the stator terminal and neutral. An investigation into the compatibility of particular generator configuration with the third harmonic scheme is important to prevent protection mal-operation since the scheme is hampered in performance by certain factors which include grounding method employed and generator terminal connection among others. In this paper, the modelling of parallel unit-connected generators of the second order is presented to study the influence of parallel unit-connected generators on third harmonic stator ground fault protection. Application of mesh analysis method to the circuit models produced ordinary non-linear algebraic equations. The equations were solved using Cramer's rule. Simulations of the circuit models were performed for no-load, light load and full load conditions using MATLAB/SIMULINK to study the character of third harmonic voltage at stator neutral and terminal when a ground fault occurs to validate the results of the models. Introduction of a ground fault at the neutral point of the single generator showed that the third harmonic voltage decreased towards zero at the neutral but increased towards maximum at the terminal.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Parallel Unit-Connected Generator Model for Third Harmonic Stator Ground Fault Protection

Adepoju¹,

Ogunjuyigbe²,

Brimmo³

2014

IJRET

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“…The zero sequence current in the earth faulty feeder is opposite to that in the sound feeders in direction in neutral point floating systems or high resistance earthed systems [11,12]. Whereas, in arcing grounding fault situation, their direction is difficult to measure [13], so the zero sequence current direction based protection has limited application [11]. Zero sequence energy is employed in [11,12] to detect arcing ground faults.…”

mentioning

confidence: 99%

Grounding Faulted Feeder Detection Methods Applied in Chinese Ineffectively Earthed Distribution Systems

Zhang

Xia

et al. 2007

2007 IEEE Industry Applications Annual Meeting

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Chinese Medium Voltage (MV) power systems have been operated with floating neutral or Petersen-coil grounded. Grounding fault current is no more than ten amperes. Traditional grounding faulted feeder detection methods based on zero sequence current have poor sensitivity in this case. In the last ten years, many novel faulted feeder detection methods have been developed in China. Some of them have widely and successfully applied in Chinese distribution systems. Four best of them (Harmonic currents comparison based fault detection, signal injection based detection, traveling wave based detection, and phase current difference based detection) are presented in the paper. The advantage and disadvantage of each method are analyzed, and problems that need further study are also brought forward.

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“…The earth fault current is usually not more than ten amperes, and the fault behavior is affected by many physical and environmental variables, such as feeder configuration, load level and type, surface condition, and weather [5][6][7]. Some high impedance earth faults are difficult to be detected [7,8]. Although several techniques have been proposed, and much progress has been made, which include zero sequence over-current protection, zero sequence current direction based protection, zero sequence wattmetric protection and some high harmonic currents based protections [9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Grounding faulted feeder detection with fault resistance measurement in mining power systems

Zhang

Li²,

Chan³

et al.

Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005.

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Many mining power systems have been operated with floating neutral or high resistance grounded. The earth fault current is no more than a few tens of amperes. Traditional earth fault detection methods based on zero sequence current have poor sensitivity in this case. For improvement, a fault detection scheme with fault current and fault resistance measurement is presented in the paper. It can detect high impedance grounding faults (HIGF). The scheme has been verified by EMTP simulation, and fault detection prototype has been developed and tested. Results show that the scheme has with high sensitivity and robustness. Keywords-mining power systems, high impedance grounding faults (HIGF), protective relaying, fault detection.I.

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Grounding and ground fault protection of multiple generator installations on medium-voltage industrial and commercial power systems II. Grounding methods

Cited by 5 publications

References 8 publications

Parallel Unit-Connected Generator Model for Third Harmonic Stator Ground Fault Protection

Parallel Unit-Connected Generator Model for Third Harmonic Stator Ground Fault Protection

Grounding Faulted Feeder Detection Methods Applied in Chinese Ineffectively Earthed Distribution Systems

Grounding faulted feeder detection with fault resistance measurement in mining power systems

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