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 sec

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

1. IntroductionEnergy is essential for societal operation and development. To meet national energy - conservation and emission - reduction policies, improving resource utilization—critical for power enterprises—is necessary. Multi - stage rural grid upgrades drive distribution transformer development. Despite high efficiency, widespread transformers still face significant overall losses due to capacity and usage issues; 70% of medium - and low - voltage grid losses come from distribu

1 Relevant Theories of Small Neutral Point Reactors in 500kV Substations1.1 Definitions and RolesA reactor is a key power system component that controls the phase relationship between AC current and voltage, divided into inductive and capacitive types. Inductive reactors limit short-circuit currents and improve stability; capacitive ones enhance transmission efficiency and voltage quality. A small neutral point reactor is a specialized type connected between a three-phase system's neutral point

1 Technical Features and Standard References of 500kV Dry - type Shunt Reactors1.1 Technical FeaturesThe 500kV dry - type shunt reactor, an oil - free power device for ultra - high - voltage transmission systems, boasts core features like advanced insulation, innovative heat dissipation, optimized electromagnetic design, and modular structure. These advantages, outperforming traditional oil - immersed reactors, also drive new technical standard demands.Advanced Insulation: Using epoxy resin cast

1 Investigation of Insulation Defects in UHV Oil - immersed ReactorsKey challenges in high - voltage oil - filled reactors during operation include insulation faults, iron - core magnetic leakage heating, vibration/noise, and oil leakage.1.1 Insulation FaultsParallel - connected reactors, once connected to the main grid’s primary coil and put into use, operate at full power long - term. Sustained high voltage raises operating temperatures, accelerating aging of coil insulation materials an

Reactors are key for reactive power compensation in power systems, with magnetically controlled reactors as a research focus. A smart grid, upgrading the traditional one via advanced tech, boosts safety and reliability, raising demands for controllable reactors. Thus, developing new - type ones matters. This paper, combining practice, explores their structural design and application to drive innovation and enhance smart grid construction.1 Functions and Application Status of Controllable Reactor