• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.2
• /
• pp.240-247
• /
• 2007

This paper presents an implementation of the generator protective relay using Real Time Digital Simulator (RTDS) user defined component (UDC) model designed to facilitate the investigation and evaluation of protective relays. The UDC for RTDS is a convenient model that allows user to develop new component models and run them on the RTDS. The developed model has major features related to the development of six models such as distance, frequency, reverse power, volts per Hz, over voltage, and out-of-step relays. Also, the generator relay models have been used to support and enhance power engineering education at both the undergraduate and graduate levels. The developed model functions are verified and tested by both static test and dynamic test. The simulation results show the capabilities of the developed generator relay using RTDS UDC.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.10
• /
• pp.1466-1473
• /
• 2017

Generally, electrical torque in synchronous generator is balanced with the rotor mechanical torque under steady-state condition. Thus, the synchronous generator rotor rotates at constant speed. However, under fault condition, the electrical torque output is suddenly decreased and the sum of both torques does not remain constant. If the mechanical torque is not decreased at the same time, the generator rotor would accelerate. Therefore, this accelerating generator rotates at different speeds with respect to other generators in the power system. This phenomena is called as Out-of-Step (OOS). In this paper, we presented a certain two-step type quadrilateral OOS relay setting, which is applicable in actual field, and examined the validity of its setting value with OOS simulation conditions due to delayed fault clearing in transmission line. In order to conduct the study of OOS relay characteristics, we checked the impedance locus and generator output characteristics under the various delayed fault clearing conditions. Moreover, we proposed a countermeasure for avoiding the misoperation of OOS relay during the stable swing by modifying the setting values.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.62 no.3
• /
• pp.133-138
• /
• 2013

A large generator is an important role in transferring an electric power to power system. The IEDs of large generator often use microprocessor technology to obtain a digital relay system with a wide range of measuring, protection, control, monitoring, and communication functions. However, all generator protection and control systems in Korea imported from abroad and are being operated. In order to reduce the large expense and improve the reliable operation, development of generator protection and control system by domestic technology is required. This paper deals with the design of the IED of generator protection panel for development of generator protection and control system. The major emphasis of the paper will be on the description of hardware and signal processing test results and measurement accuracy of the prototype IED. By developing of generator IED based on DSP and microprocessor, replacement of the generator protection panel imports are expected to be effective.

• Proceedings of the KIEE Conference
• /
• 1999.11d
• /
• pp.1044-1047
• /
• 1999

This paper deals with the dynamic property of ground overvoltage relay in large turbine generator. Relay operation is based on detecting the fundamental voltages originating from the generator. Calculations of fault voltage and current are reviewed for the neutral ground resistance. The frequency, ampitude and waveform of individual harmonics were measured using power quality analyzer and memory hi-corder at the secondary side of ground potential transformer. The ac and dc high-potential tests were applied to evaluate the condition of generator, main and auxiliary transformer, isolated phase bus, potential transformer, surge capacitor and arrester.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.8
• /
• pp.1326-1333
• /
• 2016

It is important to clear the fault and prevent resulting in damage to power system. Although the frequency of generator internal fault is relatively low, it can lead to incalculable damage to power system as well as generator. Especially, loss of field on generator can cause the generator to lose synchronism for a short time if it is not removed promptly. Therefore, it is needed to conduct research on loss of field relay for detecting or clearing the loss of field. However, the setting of the relay may vary in generator operator or engineer, and the relay is not coordinated well with other elements associated with loss of field. In this paper, we address specifically the coordination of positive offset mho loss of field relay which is one of the protection schemes for loss of field. Computer simulations are performed by using ElectroMagnetic Transients Program-Restructured Version (EMTP-RV) based on actual data.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.326-328
• /
• 2003

In this paper, in order to generator protection from a electrical fault was occurred while a generator is operated, principles of existing generator protection algorithm is examined and analyzed. and a new generator protection algorithm was developed. also, during a generator operation, Algorithm, an analysis for the basic principle of protective relay to general faults, was developed. This paper, generator was simple analyzed on the assumption that three-phase winding and observe the IEEE std.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.62 no.4
• /
• pp.198-203
• /
• 2013

There are conditions that can be unbalanced three phase currents in a large generator by untransposed lines, unbalanced loads, unsymmetrical faults, and open phases. The unbalanced conditions can producing negative sequence components of current that induce two times frequence current in the surface of the rotor, the retaining rings, the slot wedges in the field windings. These rotor currents make the rotor rapidly overheat, so the rotor can cause substantial damage in a very short time. This paper presents the digital negative sequence relay algorithm for unbalanced protection in a generator. The proposed algorithm was tested by using collected current signals on PSCAD/EMTDC considering a hydro turbine based generator control system. It can be seen that the proposed relaying by negative sequence current is useful for detection of unbalanced state of large generator.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.8
• /
• pp.1232-1238
• /
• 2009

As power facilities are getting higher at capacity, the monitoring and diagnosis of generators for fault detection and protection has attracted intensive interest. In case of an after-fault in high capacity rotating machines, the recovering cost is usually very expensive and additional time is necessary for returning in a normal situation. In this paper, we developed the protection program for the generator fault protection system and each module of the digital protective relay H/W for loading the protection program. The protective relay H/W was designed to have EMC characteristics for prohibiting from fault operation in bad power systems.

• Journal of Electrical Engineering and Technology
• /
• v.6 no.4
• /
• pp.466-473
• /
• 2011

This paper proposes a protection algorithm for a wind turbine generator (WTG) in a large wind farm. To minimize the outage section, a protection relay for a WTG should operate instantaneously for an internal fault or a connected feeder fault, whereas the relay should not operate for an internal fault of another WTG connected to the same feeder or an adjacent feeder fault. In addition, the relay should operate with a delay for an inter-tie fault or a grid fault. An internal fault of another WTG connected to the same feeder or an adjacent feeder fault, where the relay should not operate, is determined based on the magnitude of the positive sequence current. To differentiate an internal fault or a connected feeder fault from an inter-tie fault or a grid fault, the phase angle of the negative sequence current is used to distinguish a fault type. The magnitude of the positive sequence current is then used to decide either instantaneous operation or delayed operation. The performance of the proposed algorithm is verified under various fault conditions with EMTP-RV generated data. The results indicate that the algorithm can successfully distinguish instantaneous operation, delayed operation, or non-operation depending on fault positions and types.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.155-157
• /
• 2005

Digital relays have numerous advantages over traditional analog relays, such as the ability to accomplish what is difficult or impossible using analog relays. This paper presents the protective relay modeling of generator using Real Time Digital Simulator(RTDS). The developed model is applied to the test system and the simulation results are evident that they performs satisfactory.