The contact process of dynamic and static contact of transition contact. OIL SURGE RELAY is basically an Oil surge actuated relay, installed in between OLTC(on-load tap changer) and OLTC conservator tank. During tap changing, the insulating oil in the chamber will be heated, expanded, and surged by the energy generated from arc breaking. 15 m; the left part is the out port of oil flow, while its pipe does not extend into the changer cylinder. The different transition resistance coefficients are selected, the arcing energy of the main contact, arcing energy of the transition contact, and total arcing energy under various working conditions according to Equation 11 are calculated, and the arcing time is then set as 10 ms. Based on the OLTC simulation model, the oil pressure and oil flow velocity of insulating oil in the oil chamber under different transition resistance values are obtained. The increased Oil flow rate beyond the safe limit through OSR will trip the Transformer and thereby safeguarding the Transformer and OLTC. In addition, it covers the electrical safety rules, safe operating procedures and an overview of maintenance practices to give a holistic understanding of the subject. IEEE Access 7, 84803–84816. This relay also serves a third function, similar to the sudden pressure relay. Strategy Design and Transient Analysis of ITER PPEN Transformer On-Load Tap Changer during Converter Operation. Oil surge happens due to Excessive increase in Oil Volume inside Oltc tank during Switching or any kind of fault inside OLTC. Body Material: Aluminium.
Our service range includes a wide range of pressure relief valve t-6 and oil surge relay for transformer. Due to thermal and electrical stresses in the transformer, the gases are dissolved in the transformer oil. Industrial Buchholz Relay. Why not connect relay Y phase for over current and earth fault. Velocity field and pressure field of OLTC. Firstly, the 3D parameter of the OLTC is measured accurately, and the relative position of each component of the OLTC is drawn in AutoCAD according to the measurement results. On some relays, a rod is provided so that you can test both bottom and top sections by pushing the floats down until the trip points are activated. In the process of Overhauling Engineers open the who more... We are offering oil surge relay. A heavy fault inside of the OLTC incidentally generates pressure wave or Oil surge or Oil move in the direction of OLTC tank. Working Principle of Buchholz Relay This means lowering the location of the float and thus rolling the mercury switch. 2) The transition contact quick mechanism rotates 34° in total during the switching process, and the rotation angle of its moving contact during the separation of the moving and static contacts is 24°.
The connection pipe and relay cover should have 1. In this article, in Section 2, the mathematical simulation model of OLTC is established; in Section 3, the simulation result is analyzed, and besides the experimental method, the result is proposed; the change law of the oil speed and oil pressure at the top of the chamber when the OLTC operating under different transition resistances is analyzed, so as to provide guidance for the OLTC protection configuration. The Protective Oil Surge Relay (OSR) operates on the principle of Oil turbulence. It shows that the influence of switching action on the flow field in the cylinder is mainly concentrated near the moving contact and fast mechanism. This work is sponsored by the National Natural Science Foundation of China (No. Substation, its types and components 2. And the quantitative relationship between oil flow and oil pressure can be expressed by linear function.
We have attended number of Transformer in the last l0 years to the various electricity Boards & utility in all over the country & running satisfactory since attending. For the operation characteristics and fault diagnosis of the OLTC, scholars have carried out extensive research. 2017) puts forward the measurement method of the on-load tap changer current during transformer operation, and models and simulates the transformer and on-load tap changer in ATP-draw. This protective relay triggers the tripping circuit when the oil flow exceeds the specified limits, thus making the transformer to be turned off and contain the damager to the OLTC and Transformer. The Buchholz relay diagram is shown below. 3 Setting of Arcing Time, Arcing Position, and Released Energy. The quantitative mechanism research is insufficient, so it has not formed a unified conclusion. Transformers are one of the most essential and expensive element in the Power systems. Before switching, the flow in the switch cylinder is smooth, the speed is very low, and the maximum speed is just about 0. Any malfunction builds pressure which leads to increased oi more... Mercury switch type 25-80mm and oil surge relay. The applications of Buccholz relay include the following.
Your requirement is sent. Buchholz relay is actuated by the gases flowing through and accumulated in relay. Additional Information: Production Capacity: 5000. Therefore, the action of the driving mechanism is not considered in modeling.
B) The mechanism rotates by 12°, and the moving contact rotates by 24°. Locking mechanism is provided to avoid transit damage. The function of this relay depends on the mechanical phenomenon, that means it activates by mechanically. It can be seen that by increasing the applied pressure value continuously, the correct rate of oil flow relay action is gradually improved, and finally 100% correct action is achieved. The Mercury switches were connected to sensitive detecting equipment and no maloperations were recorded. These bubbles rise through the pipe between the tank and the conservator. In Figure 6, the two circular pipes on the upper part of the changer are oil flow in–out ports of the on-line oil filter, whose diameters are both 25 mm.
1007/s10894-018-0203-0. Basics of Protection system 6. Method for Diagnosis of On‐load Tap Changer Based on Wavelet Theory and Support Vector Machine. The element rotates as the oil level continues to fall and eventually the alarm switch operates.
99, that is, the quantitative relationship between them can be expressed by a linear function. Viat manufactures instruments, components and accessories for power and distribution transformers. Delivery & Payment Options. Moisture content results in the dielectric strength of oil being reduced and flashover occurs. 2015) improved the on-load tap changer of the double transition resistance branch triggered by micro-arc and established a new model of active trigger combined with the double transition resistance branch. 2016) compared and analyzed the differences of heavy gas protection setting values of different models of on-load tap changer and carried out the static action characteristic test on the gas relay of an on-load tap changer, so as to put forward suggestions on the threshold settings of the gas relay of large capacity transformers. 7 mm, the front and rear surface grid is set as 4 mm, and the grid between the four sides and the tightening bolt surface is set as 2 mm; due to the large area of the two diaphragms and insulating cylinder, the grid scale of the outer wall of the diaphragm and the inner wall of the insulating cylinder is set to 16 mm to reduce the number of grids.
B)Model of the auxiliary contact and its fast mechanism. Copyright © 2022 Zhou, Xie, Chen, Guan, Deng, Liu and Yan. 2) Through the experiment, it is found that the oil pressure corresponding to the oil speed of 1. 2) Because the movement of the tension spring at the lower part of the moving contact is difficult to simulate, while it has little effect on the transformer oil flow caused by the switching process, all the tension springs at the lower part of the moving contact are therefore removed during modeling. So, Let me interpret the major differences between them. Now d company asks in d interview d reason 4 my shud b d probable answers 4 that which may not put a negative impression. It can be seen that the smaller the transition resistance, the greater the oil flow speed and oil pressure; the greater the load, the greater the oil flow speed and oil pressure; and the greater the arcing energy, the greater the oil flow velocity and oil pressure.
Actually, there have been many cases of relay malfunctions, especially oil flow velocity relay. The results are summarized in Table 2. Buchholz Relay Applications The different types of transformer faults can protect by the Buchholz relay and that is identified by an alarm. Examples of incipient faults are: The alarm element will also operate in the event of oil leakage or if air enters the cooling system. What is Aviation Light? 13 m/s, which is close to the preset 1. Press-N-Forge All Rights Reserved. 128 W/(mK), and the specific heat capacity at constant pressure is 1. Typically, inspection windows are provided so that the amount of gas and relay operation may be viewed during testing. If the transformer has been online for some time (service aged), and gas is found in the Buchholz, oil samples must be sent to the lab for DGA and extensive testing. All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors, and the reviewers. The maximum recommended torque value should not be exceeded when making connections.
This results in gradual restoration of the apparent lost weight, until the weight of the switch cylinder predominates. Buchholz Relay Construction The Buchholz Relay consists of two elements, namely the upper element, and the lower element. Select different T1, T2, and T3 to simulate the changes of oil flow speed and pressure in the oil chamber of the transfer switch when the on-load tap changer is switched under various combinations, as shown in Table 4. Buchholz Relay Applications Buchholz Relay can use at the Entry of air bubbles in the oil Insulation failure of the Core bolt Buchholz Relay can use where the reduction of oil level will be low due to leakage This relay can use in loose and bad electrical contacts Bushing pierce The short circuit between stage Winding short circuit Operating Conditions of Buchholz Relay Buchholz relay works throughout three conditions Whenever gas bubbles formed within the transformer due to severe error. If high eddy currents, local overheating, or partial discharges occur within the tank, bubbles of resultant gas rise to the top of the tank. Precautions for Buchholz Relay Installation The conductor connection must have a paper connection while contacting the terminals instead of rubber because it may damage by the coil.
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