• Korean Journal of Computational Design and Engineering
• /
• v.19 no.1
• /
• pp.19-28
• /
• 2014

The filament winding method is widely used to manufacture products of fiber reinforced plastics (FRP), such as high pressure vessels, launch tubes and pipes. For reducing winding time, the method of winding by filament band which consists of several filament fibers is used. NC winding machine is used for precise winding and NC path is needed. Before filament winding, users should verify that winding path which presented by a line is appropriate by filament winding simulation. Also, the used length of each filament is different. So, if the peak filament exhausted, it causes to stop manufacturing. In this research, we developed software which visualizes 3D graphic of filament band winding path and simulates winding process on real time. And we proposed algorithm about calculation of each filament usage. We use geodesic equation for generating filament band surface and calculating the usage length of each filament.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.7
• /
• pp.375-381
• /
• 2004

This paper describes a three-winding transformer protective relaying algorithm based on the ratio of increments of flux linkages (RIFL). To minimize the approximation errors, the algorithm uses integration approximation. The RIFL of the two windings is equal to the turns ratio for all operating conditions except for an internal fault. For a single-phase and three-phase transformer containing the wye-connected windings, the increments of flux linkages (IFL) are calculated. For a three-phase transformer containing the delta-connected windings, the difference of IFL between the two phases are calculated to use the line currents, because the winding currents are practically unavailable. Their ratios are compared with the turns ratio. The comparative study between the proposed and differential approximation methods was conducted. The test results show that the algorithm can reduce the errors resulting from the conventional methods.

• IE interfaces
• /
• v.16 no.2
• /
• pp.185-194
• /
• 2003

This paper deals with a realistic production scheduling under a make-to-order production environment. The practical case is studied on the transformer winding process in the 'H' company. The transformer winding is a process that rolls a coil that is coated with an electric insulation material in order to generate the required voltage using the voltage fluctuation. This process occupies an important position among the production processes in the transformer manufacturing company. And this process is composed of parallel machines with different performances according to the voltage capacity and winding type. In this paper, we propose a practical heuristic algorithm for production scheduling to satisfy the customer’s due date under a make-to-order production environment. Also, we implement the production scheduling system based on the proposed heuristic algorithm. Consequently, the proposed heuristic algorithm and the implemented production scheduling system are currently working in the transformer production factory of the ‘H’ company.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.10a
• /
• pp.179-182
• /
• 2003

This research aims to establish an optimal design method of filament wound structures. So far, most design and manufacturing of filament wound structures have been based on manufacturing experiences, and there is no established design rule. In this research, possible winding patterns considering the windability and the slippage between fiber and mandrel surface were calculated using the semi-geodesic path algorithm. In addition, finite element analyses using a commercial code, ABAQUS, were performed to predict the behavior of filament wound structures. On the basis of the semi-geodesic path algorithm and the finite element analysis method, filament wound structures were designed using the genetic algorithm.

• Journal of Electrical Engineering and Technology
• /
• v.5 no.2
• /
• pp.255-263
• /
• 2010

The compensated-current-differential relay uses the same restraining current as a conventional relay, but the differential current is modified to compensate for the effects of the exciting current. Delta winding current is necessary to obtain the modified differential current for a $Y-\Delta$ transformer. This paper describes an estimation algorithm of the delta winding current and its application to a compensated-current-differential relay for a $Y-\Delta$ transformer. Prior to saturation, the core-loss current is calculated and used to modify the differential current. When the core first enters saturation, the initial value of the core flux is obtained by inserting the modified differential current into the magnetization curve. This flux value is used to derive the magnetizing current and consequently the modified differential current. The operating performance of the proposed relay was compared against a conventional current differential relay with harmonic blocking. Test results indicate that the proposed relay remained stable during severe magnetic inrush and over-excitation, and its operating time is significantly faster than a conventional relay. The relay is unaffected by the level of remanent flux and does not require an additional restraining or blocking signal to maintain stability. This paper concludes by implementing the proposed algorithm into a prototype relay based on a digital signal processor.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.194-196
• /
• 2000

This paper presents a new digital relaying algorithm for protection of a two winding power transformer. The proposed algorithm calculates mutual flux linkages of primary and secondary windings from the currents and voltages of primary and secondary windings. The mutual flux linkage ratio of primary and secondary windings is equal to the turn ratio in case of the steady state and magnetic inrush. On the other hand, the ratio is different from the turn ratio in case of internal winding faults. The algorithm does not require B-H curve. The results of various tests are satisfactory.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1450-1454
• /
• 2005

In this paper, the control strategy of the tension and speed based a prototype bio-wrap winding machine is developed. The decentralized control strategy using PID control algorithm applied for each subsystem is proposed to control the each system's desired outputs, because the tension of each subsystem effects that of next roll system. The computer simulations and the experiment results are presented to show that the proposed control scheme is feasible for a prototype bio-wrap winding machine.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.2073-2074
• /
• 2011

In this study, an algorithm for diagnosis of dc motor with winding open fault is suggested. A dc motor used in this paper, is consisted of a permanent magnet field stator, double 16-turn series winding rotating armature with 12-slot, brush and 12-commutator, etc. A current signal of dc motor which has brushes and commutatorswas considered for fault diagnosis. By commutation, this current signal shows different wave form according to the fault condition of the motor. In this study, operation of the data was easily through simplification of the current signal by the signal processing. Computation method is presented reference value($C_{dv}$) for diagnosis of winding open fault and verified through experiments that can be diagnosed using the reference value($C_{dv}$).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.8
• /
• pp.1457-1462
• /
• 2009

This paper proposes a compensating algorithm for the secondary voltage of a coupling capacitor voltage transformer (CCVT) in the time domain by considering the hysteresis characteristics of the core. The proposed algorithm estimates the three error terms i.e. the voltage across the secondary winding parameters, the voltage across the primary winding parameters, and the voltage across the capacitor and the tuning reactor. These three terms are added to the measured secondary voltage to obtain the correct voltage. The algorithm reduces the errors of the CCVT significantly both in the steady state and during a fault. The performance of the algorithm is verified under the various fault conditions by varying the fault distance, the fault inception angle, and the fault impedance with the EMTP generated data. Test results clearly indicate that the algorithm can increase the accuracy of a CCVT significantly under the fault conditions as well as in the steady state. The algorithm helps improve the performance of a protection relay or a metering device.

• Proceedings of the KIEE Conference
• /
• 2002.11b
• /
• pp.299-302
• /
• 2002

The second harmonic component is commonly used for blocking differential relay in Power transformers. However it is difficult to distinguish between inrush and internal winding fault with differential current protective relaying. This paper proposed a new method using nuro-fuzzy. The used data in nuro-fuzzy algorithm are 3-phase primary voltage and fundamental harmonic of differential current. Various states of transformer are simulated using BCTRAN and HYSDAT of EMTP. As a result of applying the algorithm in various cases, the correct discrimination between internal winding fault and inrush performed.