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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of the Korean Institute of Electrical Engineers P
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Journal DOI :
The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 57, Issue 4 - Dec 2008
Volume 57, Issue 3 - Sep 2008
Volume 57, Issue 2 - Jun 2008
Volume 57, Issue 1 - Mar 2008
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Applying Methodology for the Safety-Critical S/W Development of Railway Signaling with the Z and Statechart Formal Method
Jo, Hyun-Jeong ; Hwang, Jong-Gyu ; Yoon, Yong-Ki ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 65~71
Recently, many critical control systems are developed using formal methods. When software applied to such systems is developed, the employment of formal methods in the software requirements specification and verification will provide increased. assurance for such applications. Earlier error of overlooked requirement specification can be detected using formal specification method. Also the testing and full verification to examine all reachable states using model checking to undertake formal verification are able to be completed. In this paper, we propose an eclectic approach to incorporate Z(Zed) formal language and 'Statemate MAGNUM' which is formal method tools using Statechart for applying to the railway signaling systems.
A Hysteresis Current Controlled Resonant C-Dump Converter for Switched Reluctance Motor
Yoon, Yong-Ho ; Kim, Jae-Moon ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 72~78
The speed variation of SRM is fulfilled throughout a transition from chopping control to single pulse operation. (i,e., low speed to high speed operation). It is unsatisfied with performance at all operational regimes. In this paper, the operational performance of SRM can be improved by using current hysteresis control method. This method maintains a generally flat current waveform. At the high speed, the current chopping capability is lost due to the development of the back-EMF. Therefore SRM operates in single pulse mode. By using zero-current switching and zero-voltage switching technique, the stress of power switches can be reduce in chopping mode. When the commutation from one phase winding to another phase winding, the current can be zero as fast as possible in this period because several times negative voltage of DC-source voltage produce in phase winding. This paper is compared to performance based on conventional C-dump converter topology and the proposed resonant C-dump converter topology. Simulation and experimental results are presented to verify the effectiveness of the proposed circuit.
Evaluation of Plasma Characteristics for Hg-Ar Using LIF
Moon, Jong-Dae ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 79~83
In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. Due to this generation, the extinction of atoms in a metastable state occurred through collision, ionization, and excitation between plasma particles. The density and distribution of the metastable state depended on the energy and density of plasma particles, intensely. This highlights the importance of measuring density distribution in plasma electric discharge mechanism study. The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength. change, and also confirmed that the largest fluorescent signal in 436nm, and that the density of atoms in 546.2nm (
) were larger than 404.8nm (
). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the LIF signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.
An Investigation Into the Actual Condition of Electrical Equipments Installation and Management for Establishing the Countermeasures Against the Electric Shock in Submerged Underground
Jung, Jin-Soo ; Jung, Jong-Wook ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 84~90
This paper describes the investigation into the actual condition of electrical equipments installation and management for establishing the countermeasures against the electric shock in submerged underground. The investigation was carried out for 27 underground premises in conurbation including Seoul, and potential of the exposed electrical equipments negatively affecting on human safety when disaster occurs was measured. The objects to which measurement was carried out were as follows; electrical source; advertising lighting; power equipment. As a result, it was confirmed that potentials more than 230[V] were induced in some equipments. In addition, the electrical equipments installed in most conventional underground premises were left unmanaged.
Advanced Algorithm for IED of Stator Winding Protection of Generator System
Park, Chul-Won ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 91~95
The large AC generator fault may lead to large impacts or perturbations in power system. The generator protection control systems in Korea have been imported and operated through a turn-key from overseas entirely. Therefore a study of the generator protection field has in urgent need for a stable operation of the imported goods. In present, the algorithm using the current ratio differential relaying based DFT for stator winding protection or a fault detection had been applied that of internal fault protection of a generator. the DFT used for the analysis of transient state signal conventionally had defects losing a time information in the course of transforming a target signal to frequency domain. In this paper, the discrete wavelet transform (DWT) was applied a fault detection of the generator being superior to a transient state signal analysis and being easy to real time realization. The fault signals after executing a terminal fault modeling collect using a MATLAB package, and calculate the wavelet coefficients through the process of a muiti-level decomposition (MLD). The proposed algorithm for a fault detection using the Daubechies WT (wavelet transform) was executed with a C language and the commend line function for the real time realization after analyzing MATLAB's graphical interface. The advanced technique had improved faster a speed of fault discrimination than a conventional DFR based on DFT.
Nobel Approaches of Intelligent Load Model for Transient Stability Analysis
Lee, Jong-Pil ; Lim, Jae-Yoon ; Ji, Pyeong-Shik ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 96~101
The field of load modeling has attracted the attention since it plays an important role for improving the accuracy of stability analysis and power flow estimation. Also, load modeling is an essential factor in the simulation and evaluation of power system performance. However, conventional load modeling techniques have some limitations with respect to accuracy for nonlinear and composite loads. Thus, precision load modeling technique and reasonable application method is needed for more accurate power system analysis. In this paper, we develop an intelligent load modeling method based. on neural network and application techniques for power system. The proposed method makes it possible to effectively estimate the load model for nonlinear models as well as linear models. Reasonable application method is also proposed for stability analysis. To demonstrate the validity of the proposed method, various experiments are performed and their results are presented.
A Comparative Study on Fault Detection Algorithm of AC Generator
Park, Chul-Won ; Shin, Kwang-Chul ; Shin, Myong-Chul ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 102~108
AC generator plays an important role of power system. The large AC generator fault may lead to large impacts or perturbations in power system. And then the protection of a generator has very important role in maintaining stability in a power system. In present, the DFT(discrete Fourier transform) based RDR(ratio differential relay) had been widely applied to a internal fault of a generator stator winding. But DFT has a serious drawback. In the course of transforming a target signal to frequency domain, time information is lost. DWT uses a time-scale region. This paper proposes an advanced fault detection algorithm using DWT(discrete Wavelet transform) to enhance the drawback of conventional DFT based relaying. To evaluate the performance of the proposed relaying, we used the test data which were sampled with 720 [Hz] per cycle and obtained from ATP(alternative transient program) simulation. And we made a comparative study of conventional DFT based RDR and the proposed relaying.
Implementation and Performance Evaluation of RTOS-Based Dynamic Controller for Robot Manipulator
Kho, Jaw-Won ; Lim, Dong-Cheal ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 109~114
In this paper, a dynamic learning controller for robot manipulator is implemented using real-time operating system with capabilities of multitasking, intertask communication and synchronization, event-driven, priority-driven scheduling, real-time clock control, etc. The controller hardware system with VME bus and related devices is developed and applied to implement a dynamic learning control scheme for robot manipulator. Real-time performance of the proposed dynamic learning controller is tested and evaluated for tracking of the desired trajectory and compared with the conventional servo controller.
States Estimation of Nonlinear Stochastic System Using Single Term Walsh Series
Lim, Yun-Sik ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 115~120
The EKF(Extended Kalman filter) method which is the state estimation algorithm of nonlinear stochastic system depends on the initial error and the estimated states. Therefore, the divergence of the estimated state can be caused if the initial values of the estimated states are not chosen as approximate real state values. In this paper, the demerit of the existing EKF method is improved using the EKF algorithm transformated by STWS(Single Term Walsh Series). This method linearizes each sampling interval of continous-time system through the derivation of an algebraic iterative equation without discretizing continuous system by the characteristic of STWS, the convergence of the estimated states can be improved. The validity of the proposed method is checked through comparison with the existing EKF method in simulation.
Loss Analysis of Three Phase Induction Motor Connected to Single Phase Source
Kim, Do-Jin ; Jwa, Chong-Keun ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 121~126
This paper analyzes the losses of a Steinmetz connection three-phase induction motor which is supplied by a single-phase source. The T-type equivalent circuit which is taken no-load losses into account is used to determine phase converter capacitive reactances at starting and rated speed by using the condition of the minimum voltage unbalance. The starting and the operating capacitor are replaced at the slip of the same voltage unbalance factor points which are depicted using two capacitive reactances. The operation characteristics are investigated by comparing with those of three-phase balanced operation to find the feasibility of single-phase operation. To analyze the losses of this motor, the output power decrease factor(OPDF), the loss ratio(LR), the no load loss ratio(NLLR), the copper loss ratio(CLR), the stator copper loss ratio(SCLR), and the rotor copper loss ratio(RCLR) are defined and simulated in the whole slip range. The simulated results show that OPDF is maintained almost uniformly, LR is low at low speed and high at high speed, CLR is higher !ban NLLR, but CLR varies concavely and NLLR varies convexly at high speed, SCLR is low at low speed and high at high speed, but SCLR varies convexly at high speed, and RCLR is nearly opposite to SCLR.
Robust Adaptive Backstepping Control of Induction Motors Using Nonlinear Disturbance Observer
Lee, Eun-Wook ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 127~134
In this paper, we propose a robust adaptive backstepping control of induction motors with uncertainties using nonlinear disturbance observer(NDO). The proposed NDO is applied to estimate the time-varying lumped uncertainty which are derived from unknown motor parameters and load torque, but NDO error does not converge to zero since the derivate of lumped uncertainty is not zero. Then the fuzzy neural network(FNN) is presented to estimate the NDO error such that the rotor speed to converge to a small neighborhood of the desired trajectory. Rotor flux and inverse time constant are estimated by the sliding mode adaptive flux observer. Simulation results are provided to verify the effectiveness of the proposed approach.
Fabrication and Properties of MFISFET Using
Jung, Soon-Won ; Koo, Kyung-Wan ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 135~139
MFISFETs with platinum electrode on the
/aluminum nitride/Si(100) structures were successfully fabricated and the properties of the FETs have been discussed.
characteristics of MFISFETs for linear region (that is, 0.1 V of the drain voltage) showed hysteresis loop with a counter-clockwise trace due to the ferroelectric nature of
films. A memory window (i.e., threshold voltage shift) of the fabricated device was about 2[V] for a sweep from -4 to +4[V]. The estimated field-effect electron mobility and transconductance on a linear region were 530[
] and 0.16[mS/mm], respectively. The drain current of 27[
] on the "on" state was more than 3 orders of magnitude larger than that of 30[nA] on the "off" state at the same "read" gate voltage of l.5[V], which means the memory operation of the MFISFET.
A Study on the Electrical Characteristic of Organic Thin Film by Physical Vapor Deposition Method
Park, Su-Hong ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 140~145
The purpose of this paper is to discuss the fabrication of
) organic thin films using the vapor deposition method. Vapor deposition was performed under the following conditions: the temperature of evaporator, the applied electric field, and the pressure of reaction chamber were
, 142.4 kV/cm, and
, respectively. The molecular structure of the evaporated organic thin films were evaluated by a FT-IR. The results showed that the characteristic absorption peaks of
-form crystal increase from 72% to 95.5% with an increase in the substrate temperature. In the analysis of the electric characteristics, the abnormal increases in the relative dielectric constant and the dielectric loss factor in the regions of low frequency and high temperature are known to be caused by inclusion of impurity carriers in the PVDF organic thin films. In order to analyze quantitatively the abnormalities in the conductivity mechanism caused by ionic impurities, the product of the ion density and the mobility that affect the electrical property in polymeric insulators is analyzed. In the case of a specimen produced by varying the substrate temperature from
, the product of mobility and the ion density decreased from
. This result suggests that the higher the substrate temperature is maintained, the better excluded the impurities are, and the more electrically stable material can be obtained.
A Study on the HEC(Hybrid ESE-Conductor) Method for Lightning Protection of Buildings
Kim, Dong-Jin ; Kim, Young-Sun ; Lee, Ki-Sik ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 146~152
The frequency of lightning is increased due to improbable weather condition and global wanning. This phenomenon increases economical damage as well as human damage. Advanced countries like europe and north america have applied the facility standard of lightning by accumulating a store of quantitative data about lightning research. Lightning facility is composed of the lightning accepting part for induction lightning, ground connected electrode which conducts lightning current. The lightning accepting part is composed of normal rod, horizontal conductor, ESE lightning rod. Moreover, lightning accepting part is taken to use by the method of protection. This paper suggests HEC(Hybrid ESE-Conductor) method which mixes horizontal conductor and ESE lightning rod. This is also discovered by experiment that the starting point of corona discharge current is low, so it is efficient for lightning protection comparing with other methods. Moreover, distribution of electric field is analyzed qualitatively by finite element method. It also results in the relation of the starting point of corona discharge current. Corona discharge current makes minute current about some
between the electrodes by the strength of electric field. Also it occurs insulation destruction of gas, and it is developed to the shape of streamer by increase of the strength of electric field. We can find that the initial occurrence of streamer and contact probability of lightning can have advantage after researching the starting point of corona discharge current and discharge current of lightning striking point. This research demonstrates that the suggested HEC method is economically competitive as a lightning protection facility, and it takes a capably perfect role.
Absolute Evaluation Method to Obtain Ratio Error and Phase Displacement of Current Transformers
Kim, Yoon-Hyoung ; Jung, Jae-Kap ; Han, Sang-Gil ; Koo, Kyung-Wan ; Han, Sang-Ok ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 153~159
We have developed an absolute evaluation method to obtain the ratio error and phase displacement of a current transformer (CT) without any precise standard CT by measuring four parameters in a CT equivalent circuit. The excitation admittance in the CT equivalent circuit can be obtained by employing standard resistors with negligible reactive component. The secondary leakage impedance in the CT equivalent circuit can be measured using a universal impedance bridge. The method was applied to CTs under test with the wide current ratios in the range of 5 A / 5 A - 5,000 A / 5 A and 5 A / 1 A - 5,000 A / 1 A. The ratio error and phase displacement of the CT under test obtained in this study are consistent with those measured at the national institute in Canada using the same CT under test within an expanded uncertainty (k = 2) in the overall current ratios.
Auto-Diagnosis for Stator Winding Faults Using Distortion Ratio of Park's Vector Pattern
Song, Myung-Hyun ; Park, Kyu-Nam ; Han, Dong-Gi ; Yang, Chul-Oh ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 160~163
In this paper, an auto-diagnosis method of the stator winding fault for small induction motor is suggested. 3-phase stator currents are sampled, filtered, and transformed with Park's vector transformation. After then Park's vector patterns are obtained. To detect the stator winding fault automatically, a distortion ratio is newly defined and compared with the one of healthy motor, and the threshold levels of distortion ratio are suggested. The 2-turn, 4-turn, 8-turn winding fault are tested with no load, 25%, 50%, 75%, and 100% rated load. The distortion ratio of the Park's vector patterns are increased as the increase of the faulted turns, but are same as the increase of the load.
Establishment of National Standard System for 240 kV High Voltage Transformer
Jung, Jae-Kap ; Kwon, Sung-Won ; Lee, Sang-Hwa ; Kang, Jeon-Hong ; Kim, Myung-Soo ; Han, Sang-Gil ; Kim, Yoon-Hyoung ; Han, Sang-Ok ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 164~169
National standard system for calibrating voltage transformer(VT) up to primary voltage of 240 kV have been established in 2005. The system consists of voltage source, regulating unit, VT testing unit, standard VT, VT under test and VT burden. To verify and validate the performance for 240 kV VT calibration system, the comparison with the National Measurement Institute of Australia(NMIA) has been performed using same VTs. The comparison results of the VTs mesured at the Korea Research Institute of Stansdards and Science(KRISS) are consistent with those measured at NMIA within 0.002 % for ratio error and 0.14 min for phase displacement in the primary voltage ranges of Vp = 3300 V - 22000 V with a secondary voltage of Vs = 110 V.
A Technique for a Short-Circuit Current Calculation to The Single-Phase Transformer in the Three-Phase Systems
Park, Jae-Hwae ; Jin, Tae-Seok ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 170~175
This paper describes the exact short-circuit current calculation technique for the single-phase transformer which is installed in the three-phase systems and shorted in the secondary side. Not only the results for a short-circuit current calculation in the existing literatures are wrong, but also little literature deals with the short-circuit current for a single-phase transformer. So, this paper presents a theoretical study and calculation method for a single-phase short current. The validity of the presented method is investigated through Simulation using "Power Tools" and "PSim" program.
On-line Insulation Diagnostic by PD Monitoring Field Practical of UHF Technique for On-line PD Monitoring
Oh, Yong ; Choi, Yong-Sung ; Hwang, Jong-Sun ; Lee, Kyung-Sup ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 176~180
A field-oriented UHF system for on-line PD monitoring of transformers is designed, which has been installed inside the oil tank of transformer in a substation by two ways: on-line installing mode through the oil-valve and pre-installing mode through the man hole/hand hole cover. This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.
A Study on the Development and Estimation of Waterproof Outlet for Low Voltage
Choi, Chung-Seog ; Kim, Chang-Soung ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 181~185
In this paper, we investigates accident actual conditions of electric outlet for low voltage that is used into interior and clear hazardous factor. Electric outlet for general can know that melting of socket-outlet and carbonization of support occur if a contaminant becomes burnout because is flowed in. Existent outlet consists of structure that special quality is good but inflow of a contaminant is easy when is dry. But, waterproof outlet passes silicon layer and have connected structure plug. As developed outlet covers whole surface and back side, interval was shut. Safety pin of developed outlet was established to operate to vertical direction. Therefore, we estimate that contribute on prevention of electrical disaster if use developed outlet to a restaurant, a laundry, a laboratory etc.
Analysis of Electrical Installation Survey at Conventional Markets
Lee, Sang-Ick ; Jeon, Hyun-Jae ; Kim, Gi-Hyun ; Bae, Seok-Myung ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 186~191
The conventional markets is badly damaged by a big fire because of no proper fire fighting management system. The cause of electricity fire is the aging and contact badness of electric equipment. The supervisory detecting system is needed to develop because the electric equipment is located to non visible and non exposing place. In this paper, we investigated the receiving and distributing board, the panel board and the fire prevention system of 17 domestic conventional markets. As a result of survey, capacity of distributing boards is mainly 600A and materials of distributing boards are synthetic resins 49%, metal 44%. ELB is mainly used as branch circuit breaker.
Amplification of Current Harmonics Due to Self-Excitation Capacitors for Wind Induction Generators
Oh, Yong ; Choi, Yong-Sung ; Hwang, Jong-Sun ; Lee, Kyung-Sup ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 192~197
The value of this paper is to use reduced size apparatuses to perform field measurement in order to identify and validate that the harmonic-current effects are due to the presence of self-excitation capacitance connected at stator's terminals of the studied SEIG. This paper has presented the measured electrical quantities of a three-phase
-connected wind induction generator (WIG) under sudden connection and disconnection of resistive loads. An intelligent power-system recorder/monitor has been employed to measure three-phase voltages and currents of the studied system at the terminals of the studied WIG and the load. The measured electrical quantities have been analyzed. Total harmonic distortion (THD) of current using cumulative probability density function has been employed to determine the penetration of harmonic distortion at load side. The results show that the harmonic currents generated by the studied WIG can be severely amplified by the connected self-excited capacitance at the stator's terminals.
Characteristics of a Flux-Lock Type Superconducting Fault Current Limiter According to the Parallel Connection of the Superconducting Elements.
Oh, Kum-Gom ; Jung, Byung-Ik ; Choi, Hyo-Sang ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 198~201
We investigated the operating characteristics of the flux-lock type superconducting fault current limiter(SFCL) with the parallel connection between the primary and secondary windings which are connected with two superconducting units in series. The parallel connection for current level increase of the flux-lock type SFCL is necessary to apply the SFCL into the power system. The resistance generated in superconducting units was dependent upon the winding direction of the primary and the secondary coils, which can reduce the power burden. The resistance of the superconducting elements in the subtractive polarity winding is higher than that of the additive polarity winding. The fault current limiting effect of the subtractive polarity winding is better than that of the additive polarity winding. From this results, we confirmed that the power capacity of the flux-lock type SFCL could be increased by the parallel connection of the superconducting units.
On-Line Condition Monitoring of Electrical Equipment Using Temperature Sensor
Choi, Yong-Sung ; Kim, Sun- Jae ; Kim, Yeong-Min ; Song, Hwao-Kee ; Lee, Kyung-Sup ;
The Transactions of the Korean Institute of Electrical Engineers P, volume 57, issue 2, 2008, Pages 202~208
Condition monitoring technologies allow achieving this goal by minimizing downtime through the integrated planning and scheduling of repairs indicated by condition monitoring techniques. Thermal runaways induced by conduction problems deteriorate insulating material and cause disruptive dielectric discharges resulting in arcing faults. Therefore, having the ability to directly measure the temperature of the contacts while in service will provide more information to determine the true condition of the equipment. It allows connective measures to be taken to prevent upcoming failure. Continuous temperature monitoring and event recording provides information on the energized equipment's response to normal and emergency conditions. On-line temperature monitoring helps to coordinate equipment specifications and ratings, determine the real limits of the monitored equipment and optimize facility operations. Using wireless technique eliminates any need for special cables and wires with lower installation costs if compared to other types of online condition monitoring equipment. In addition, wireless temperature monitoring works well under difficult conditions in strategically important locations. Wireless technology for on -line condition monitoring of energized equipment is applicable both as stand alone system and with an interface for power quality monitoring system. The paper presents the results of wireless temperature monitoring: of electrical equipment at a power plant.