37results about How to "Good equivalence" patented technology

The invention discloses a method for testing instantaneous forward voltage in a dc converting valve recovering period, which belongs to the power electronics and electric system field, and comprisesfollowing steps: taking a specimen valve VT as a back to back 6 impulse bridge whose one bridge arm is connected with a high pressure little current source circuit, connecting in series impulse voltage generators on two ends of the VT, connecting with a circuit which is connected in parallel between an auxiliary valveV1 and a low-pressure large electric current source, and adding a pulse trigger into the circuit in a testing period. A time sequence process comprises following steps:, t0-t1, controlling the 6 impulse bridge to trigger an angel alpha, operating in inversion, triggering and conducting valve VT and valve V1 through t1time, introducing a half wave direct current, a zero-crossing half wave current t2 which is from a large electric current circuit, switching off the V1, t2-t3, switching off the V1, wherein a little electric current of a valve arm which contains the VT transverses through the specimen valve, zero-crossing and switching off t3 and VT, providing specimen voltagethrough a high pressure little current source back to back circuit, t3-t4, and loading the impulse voltage on the specimen valve. The method can satisfy an energy taking requirement for the specimenvalve and have wide specimen range and good equivalence.

A method and instrument for calibrating a neutral point grounding device of a multifunctional distribution network, which simulates a high-resistance grounding fault of a distribution network and Fault characteristic quantity of low-resistance ground fault; simulate permanent ground fault and instantaneous ground fault of distribution network by adjusting three-phase voltage value, neutral point voltage value, zero-sequence current value of each circuit and duration of zero-sequence current of circuit and the fault feature quantity of disconnected grounding fault; by adjusting the capacitance and its change of the adjustable capacitor module to simulate the capacitance current of the distribution network and the state characteristic quantity of the change; for different types of neutral point grounding devices of the distribution network After the secondary circuit of the distribution network neutral point grounding device inputs the distribution network simulated ground fault characteristic quantity or the simulated state characteristic quantity, the logic function and wiring correctness of the distribution network neutral point grounding device are verified.

The invention relates to an electrocorrosion acceleration test method for a DC (direct current) porcelain insulator iron cap. The method comprises the following steps: 1, cleaning the dirt on the surface of a porcelain insulator, and placing in a shade for drying and avoiding direct sunlight; 2, sticking a copper sheet to the surface of the porcelain insulator, realizing short circuit for creepage distances of the lower surface and the partial upper surface of the porcelain insulator, and forming a certain distance between the electrode of the copper sheet and the iron cap; 3, placing the porcelain insulator stuck with the copper sheet in a liquid environment simulation chamber, and adopting a dripping method to test, wherein the water drops above the porcelain insulator are dripped to gather in the gap between the iron cap on the lower side of the porcelain insulator and a porcelain surface and form a more concentrated liquid contact point; 4, selecting annual average leakage quantity of electric charge as a basis and testing; and 5, dissecting the electrocorrosion part of the porcelain insulator iron cap, and measuring the length, width, depth and corrosion direction of the electrocorrosion area. According to the invention, the testing steps are rigorous, the practicability is strong, the testing result has better equivalence with the electrocorrosion situation of the porcelain insulator on site, and the electrocorrosion acceleration test method can be widely applicable to the experimental research on the electrocorrosion problem of the DC porcelain insulator iron cap.