Influence of Switching Conditions on the VETO Magnitudes in a GIS
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Estimation of very fast transient overvoltage (VFTO) has been carried out using EMTP for various switching conditions in a 420 kV gas-insulated substation (GIS). The variation of the VFTO peak along the GIS bus nodes for disconnector and circuit breaker switching operations, as well as the variation of VFTO peak with different magnitudes of trapped charges, have been studied. The results indicate a distinct pattern of variation of VFTO peak along the nodes of the GIS bus in the case of disconnector switch operation as compared to that of circuit-breaker operation. It has also been noticed that the variation of VFTO peak levels are not in direct proportion to the trapped charge present on the HV bus.Keywords:
Disconnector
Overvoltage
Emtp
Transient (computer programming)
Variation (astronomy)
The very fast transient overvoltage (VFTO) generated during switching of disconnector in HGIS or GIS may affect the safe and stable operation of electric equipment, especially with large-scale application of electronic equipment in intelligent substation, the impact will be more serious. The test system and method of external VFTO and TEV on HGIS is comprehensive introduced in this paper. It is texted in 500kV substation that is the first completely intelligent substation. With compared the test results, the waveform characters and frequency components of the whole process of VFTO were proposed and the effects of VFTO to intelligent equipment were analysis. The ability of the main electric equipment to withstand VFTO is checked. The measured data can explore phenomena and laws of VFTO on intelligent substation, provided the basis to the insulation coordination of intelligent equipment and give a reference for the subsequent construction projects of intelligent substation.
Disconnector
Overvoltage
Transient (computer programming)
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Switching transients are an important factor on the equipment selection, protection and tower air clearances. Lightning and switching are two primary causes of transient overvoltage in power systems. This paper focuses on a comparative study of the modeling and simulation of a switching transient overvoltage study using two widely used simulation tools: PSCAD/EMTDC and EMTP-RV. The overvoltage modeling and statistical analysis method have been carefully described in both simulations. The comparative overvoltage results for switching transient study are also provided.
Overvoltage
Emtp
Transient (computer programming)
Transient analysis
Power system simulation
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Switching transients are an important factor on the equipment selection, protection and tower air clearances. Lightning and switching are two primary causes of transient overvoltage in power systems. This paper focuses on a comparative study of the modeling and simulation of a switching transient overvoltage study using two widely used simulation tools: PSCAD/EMTDC and EMTP-RV. The overvoltage modeling and statistical analysis method have been carefully described in both simulations. The comparative overvoltage results for switching transient study are also provided.
Overvoltage
Emtp
Transient (computer programming)
Transient analysis
Power system simulation
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Citations (6)
A disconnector for an overvoltage protector is equipment that disconnects a circuit when the overvoltage protector may fail in a short circuit mode. The disconnector and the overvoltage protector are connected in series. A fuse or a circuit breaker is normally used as a disconnector. However there are problems with both methods. A fuse is not recyclable once it goes out. Even a circuit breaker is resettable, a lightning surge current causes a switchgear of circuit breaker to open unnecessary. This malfunction spoils the overvoltage protective function which eliminates a lightning surge current into an instrument. If the problem which a switchgear of circuit breaker comes floating can be solved, even when a lightning surge current flows through it, an instrument can be protected by the overvoltage protector. This paper presents several approaches preventing circuit breaker type disconnectors from the malfunction.
Disconnector
Overvoltage
Switchgear
Fuse (electrical)
Surge arrester
Distribution board
Recloser
Lightning
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This paper analyzes the lightning-induced overvoltage and current in buried underground distribution cable. Based on analytical expressions, the lightning-induced overvoltage and current in buried underground distribution cable is calculated by EMTP/MODELS. The modeling is verified by comparing with the results in reference. Also, the type and buried arrangement of cables used in domestic distribution line are modeled by EMTP/ATPDraw. The various simulations according to the type and buried arrangement of cable are performed and the simulation results are analyzed.
Emtp
Overvoltage
Lightning
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This paper discusses the disadvantages of moving contact loosing, escaping from the closing position because of the hard bus connection between the circuit breaker and the disconnector. The improvement of reforming the hard bus connection to a soft one between 40.5 kV circuit breaker and disconnector is made in Zhuozhou 220 kV substation. The author also gives the method to solve this kind of problem.
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This paper describes the suppression of the transient overvoltage caused by gas disconnector switching of a small capacitive charging current in a gas insulated switchgear substation. The overvoltage is suppressed by the insertion of a resistor with an appropriate value during the switching. A scale model gas disconnector with the resistor is developed. The overvoltage suppression effect and the charging current breaking capability of the gas disconnector are experimentally confirmed. A prototype ultra high voltage gas disconnector is trial manufactured and tested.
Disconnector
Switchgear
Overvoltage
Transient (computer programming)
Sulfur hexafluoride
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The 500 kV GIS disconnector of a pumped storage power station is detected to have the risk of operating overvoltage breakdown of the gas chamber. In this paper, the causes of the operating overvoltage of the disconnector of GI equipment are analyzed, and the insulation impact of the overvoltage generated during the operation of the disconnector at different positions on the adjacent equipment is studied, Finally, the possibility of reducing switching overvoltage by changing the contact of disconnector and adding closing resistance is introduced.
Disconnector
Overvoltage
Switchgear
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A disconnector for an overvoltage protector is equipment that disconnects a circuit when the overvoltage protector may fail in a short circuit mode. The disconnector and the overvoltage protector are conected in series. A fuse or a circuit breaker is normaly used as a disconnector. However there are problems with both methods. A fuse is not recyclable once it goes out. A circuit breaker is resetable, a lightning surge current causes a swich of circuit breaker to open unnecessary. This malfunction degrades the overvoltage protector function which eliminates a lightning surge current into an instrument. If the problem which a switch of circuit breaker comes floating can be solved, even when lightning surge flows through it, an instrument can be protected by the overvoltage protector. This paper presents a way of preventing an circuit breker type disconnentor from the malfunction.
Disconnector
Overvoltage
Fuse (electrical)
Surge arrester
Distribution board
Residual-current device
Lightning
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According to the theory of restrike overvoltage at switching on or off the unloaed bus and integrating with typical circuit in 220kV test substation,this paper presents a computer model that can simulate the overvoltage.The model utilizes electromagnetic transients program(EMTP),and it possess reliable accuracy and stability of numerical calculation.
Overvoltage
Emtp
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