35 results about "Transient recovery voltage" patented technology

The invention relates to an instantaneous-fault identification method for beat frequency detection adopting recovery-voltage delay one-half cycle superposition and belongs to the field of power system relay protection. The method includes that for an electric transmission line with two ends provided with paralleling reactors, calculating the free oscillation component frequency omega and the oscillating period tau according to line parameters and compensation degree of the paralleling reactors; when line failure occurs and at the moment starting from 200ms after a breaker is disconnected, superposing disconnected-phase voltage values acquired by a measuring end and voltage values of current values 10ms ago, and extracting frequency omega j (j=1,2,3) of superposed waveforms within three sliding time windows by the aid of discrete Fourier transformation, wherein each of the sliding time window is 2 tau in length; respectively comparing and extracting size relation of the omega j and the omega, and if the extracted frequency is equal to the calculated free oscillation frequency, judging to be instantaneous fault, or otherwise, judging to be permanent fault. As is show in a great deal of simulation tests and verification, the instantaneous-fault identification method is reliable and efficient.

The invention discloses an airflow control element with a shielding function, one structure of the airflow control element is composed of a base body fired by a polytetrafluoroethylene material and ashielding element embedded in the base body, the base body is of an annular structure and is provided with a streamline outer surface, and the top of the base body is a throat area; and the other structure is formed by superposing a shielding substrate made of an aluminum material or a copper material or a steel material with an arc-combustion-resistant coating sprayed on the outer surface, and the top of the shielding substrate is a throat area. A shielding function is achieved while airflow is controlled, SF6 high-pressure airflow is guided and controlled in the large-current breaking process of a circuit breaker, the maximum field intensity under transient recovery voltage is controlled, and the control requirement of the high-voltage circuit breaker for the large-current breaking performance and the electric field intensity under the transient recovery voltage is met; the electric field distribution of the moving and static contacts under the transient recovery voltage is effectively improved, and the difficulty of the circuit breaker in breaking large current is reduced.

The invention relates to a high-pressure gas breaker breaking performance assessment method and system. The method comprises the following steps of: carrying out magnet dynamic simulation on an arcing process of a high-pressure gas breaker to obtain total arc voltage and arc current before the arc current crosses zero; extracting model parameters of a preset zero area arc model; taking the total arc voltage and the arc current as initial conditions to solve past-arc current under the action of transient recovery voltage on the basis of the zero area arc model; judging whether the high-pressure gas breaker causes thermal breakdown or not in the breaking process according to change trend of the past-arc current; obtaining pressure intensity distribution and temperature distribution in an arc extinction chamber under the action of the past-arc current through magnet dynamic simulation, comparing field intensity, caused by the action of the transient recovery voltage, at each point of the arc extinction chamber, corresponding temperature and critical breakdown field intensity, and assessing the probability of electric breakdown in the arc extinction chamber. By adoption of the method and system provided by the invention, the comprehensive assessment for the past-arc thermal breakdown and electric breakdown characteristics of the high-pressure gas breaker is realized.

A circuit breaker having at least one capacitor assembly connected in parallel across a contact of the circuit breaker. The capacitor assembly can be housed with the contact within a sealed enclosure of the circuit breaker. The enclosure can be configured to house an insulating medium that is configured to reduce or quench an arc(s) that may form at least when the contact of the circuit breaker is displaced from a closed position to an open position. The capacitor assembly, which includes a transient recovery voltage (TRV) capacitor, can be configured to delay terminal fault and short line fault TRV and the rate of rise of the initial TRV (ITRV) that can appear across the open contact of the circuit breaker. By being connected in parallel across the contact, the capacitor assembly can be connected to either side of the contact, regardless of whether the contact is in an open position or closed position.

The invention relates to a method for calculating a transient recovery voltage (TRV) waveform parameter. A plurality of tangent lines required in a standard are calculated through TRV waveform rotation, so that the parameter of a TRV waveform is obtained, human errors are reduced, the primitiveness of data is ensured, and the accuracy of test data analysis is increased. The method has the advantages of intuition and visualization of a graphic-art technique, and has the advantages of convenience and high efficiency simultaneously; the test efficiency is increased. The accurate TRV parameter obtained through the method can be taken as a reference for test personal to adjust a test loop parameter, so that the breaking property of a tested circuit breaker can be checked more accurately, and technical support is provided for the safe running of an electric power system.

The invention provides a switching power supply device capable of ensuring the transient recovery of the voltage discharge of an electrolytic capacitor after the rectifying process, without the addition of power consumption. The switching power supply device comprises a rectifying circuit used for rectifying the AC voltage; an electrolytic capacitor used for rectifying and smoothing the AC voltage; a transformer used for applying a smoothed voltage onto the electrolytic capacitor; a switching element connected to the transformer (T); and a control circuit (Z1) used for enabling the switching on / off of the switching element. The control circuit (Z1) is composed of a start-up circuit (Z10) and a discharge circuit (Z14). The start-up circuit (Z10) is used for supplying the voltage of the electrolytic capacitor to the Vcc terminal of the control circuit (Z1). The discharge circuit (Z14) is connected with the Vcc terminal and is used for discharging the transient recovery voltage of the electrolytic capacitor.

The chamber (1) has a tubular shaped arc blast isolating nozzle (5) extending along a longitudinal axis (XX'). A movable contact (3) includes a hollow inner tube (30) whose end is connected to a contact portion (31) of the movable contact, where arc blowing is entirely realized inside of the hollow tube along the longitudinal axis of the chamber. A neck (304) is provided in upstream of the contact portion for passage of gas. A release portion (305) is provided between the neck and the contact portion for passage of gas. An independent claim is also included a high-voltage direct-current conversion substation comprising a thyristor through which opening of a loading valve is realized.

The method for extracting the characteristic parameters of the envelope of the transient recovery voltage waveform proposed by the invention can judge the characteristics of the TRV waveform according to the test voltage and the test mode, and automatically extract the characteristic parameters of the envelope. This extraction method has a small amount of calculation and is more accurate in calculation, which ensures the originality of the data, and does not cause the "Rongge" phenomenon to occur locally due to the use of polynomial fitting.