Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

1 OverviewCases of transformer oil contaminated by microorganisms have been reported both domestically and internationally. Individual transformer manufacturers, user units, and research institutions have conducted specialized studies, but all focused on power transformers. This paper targets specialty transformers for specific applications (e.g., rectifier transformers for graphitization furnaces, submerged arc furnace transformers), exploring the process of microbial contamination of their tra

Contradiction PointsIn automatic tracking arc suppression coils, the adjustment precision is high, the residual current is small, and the operation is close to the resonance point.In an automatic tracking arc suppression coil grounding system, two factors must be considered: Under normal operating conditions, the long-term voltage displacement of the neutral point should not exceed 15% of the system's nominal phase voltage; In the case of a ground fault, the grounding residual current should b

1 Hardware Design of Tester Power SupplyThis device uses a standard small - signal generating device to generate small - current signals with the required frequency and phase angle. Then, through the amplifying circuit and phase - modulating circuit, the working power supply is generated.1.1 Power Frequency Sine Wave Small - Current Signal Generating DeviceThe sine wave generating circuit is mainly composed of the waveform generating chip MAX038 produced by MAXIM Corporation of the United States

1 Error Analysis of Traditional Turn Ratio Testing MethodsThe QJ35 turn ratio bridge and other single-phase-phase-based testers all use the double-voltmeter principle. The QJ35, however, eliminates power supply fluctuation interference via bridge balance. For three-phase transformer ratio testing with a single power supply, corresponding terminals must be shorted and data converted, turning three-phase tests into independent single-phase measurements, with √3 Yd conversion based on con

A certain special transformer manufacturing enterprise, which has been producing special transformers such as split - phase - shifting rectifier transformers, rectifier transformers for electrolysis, and transformers for submerged arc furnaces for more than 20 years. Now, an evaluation is made on the production process flow and its characteristics of the special transformers after the company's transformation.1.Production Process Flow Chart of Special TransformersThe production of special transf

Transformer Connection GroupThe connection group of a transformer refers to the phase difference between the primary and secondary voltages or currents. It is determined by the winding directions of the primary and secondary coils, the labeling of their start and end terminals, and the connection mode. Expressed in a clock-like format, there are 12 groups in total, numbered from 0 to 11.The DC method is commonly used to measure the transformer's connection group, mainly to verify whether the con

Working VoltageThe term "working voltage" refers to the maximum voltage that a device can withstand without sustaining damage or burning out, while ensuring the reliability, safety, and proper operation of both the device and associated circuits.For long-distance power transmission, the use of high voltage is advantageous. In AC systems, maintaining a load power factor as close to unity as possible is also economically necessary. Practically, heavy currents are more challenging to handle than hi

The sequence for shutting down a main transformer is as follows: when de-energizing, the load side should be shut down first, followed by the power supply side. For energizing operations, the reverse order applies: the power supply side is energized first, then the load side. This is because: Energizing from the power supply side to the load side makes it easier to identify the fault range and take prompt judgment and handling measures in case of a fault, preventing the fault from spreading or e

Let's take an auxiliary power system with two station transformers as an example. When one station transformer needs to be out of service, there are two operation methods: non-interruptive power supply and instantaneous power interruption. Generally, the method of instantaneous power interruption on the low-voltage side is preferred.The operation method for instantaneous power interruption on the low-voltage side is as follows: Open the 380V power incoming circuit breaker of the corresponding se

Definition of Voltage StabilityVoltage stability in a power system is defined as the ability to maintain acceptable voltages at all buses under both normal operating conditions and after being subjected to a disturbance. In normal operation, the system’s voltages remain stable; however, when a fault or disturbance occurs, voltage instability may arise, leading to a progressive and uncontrollable voltage decline. Voltage stability is sometimes referred to as "load stability."Voltage instability c