High - Speed Earth Switches (HSES) have two rated operating sequences:C–ti1–OC–ti1–O–ti2–C–ti1–Owhere:ti1 represents a time period that is longer than the time needed for secondary arc extinction and for the dielectric recovery of air insulation at the fault location. ti1 is determined by users while taking system stability into account. The recommended value of ti1 is 0.15 s.ti2 is the intermediate time specified by the system protection. ti2 enco

IntroductionIn the complex landscape of power distribution, distribution transformers play a pivotal role. These transformers are tasked with stepping down voltage from the primary distribution levels to the appropriate utilization voltages for end-users. Their proper functioning is crucial for maintaining a stable and efficient power grid. This article delves into two essential aspects of distribution transformer assessment: thermal performance testing and mechanical performance testing, while

General Rules for GIS Grounding and bondingIn most Gas - Insulated Switchgears (GIS), there are two grounding grids:The station grounding grid, which is analogous to that in a typical Air - Insulated Switchgear (AIS) installation.The GIS grounding mesh, a closely - spaced grounding grid embedded in the concrete slab where the GIS is installed.Typical rules for GIS grounding and bonding are as follows:All grounding conductors should be kept as short as feasible.The grounding mesh and its intercon

Advanced Power Quality ManagementUnlike passive filters, active filters do not generate connection overvoltages, as the charge is not trapped in capacitors in the same way. The typical structure of active filters comprises an inductor, namely a filter coil, and a power electronic converter, that is, switches and capacitor - based energy storage.The active filter converter is usually controlled to generate opposite - phase harmonic waveforms, thereby reducing or eliminating harmonic propagation.

Definition of Transformer LossesTransformer losses can be mainly categorized into two types: no - load losses and load losses. These losses are ubiquitous across all types of transformers, irrespective of their application scenarios or power ratings.However, there are two additional types of losses: extra losses induced by harmonics, and losses that are especially relevant for larger transformers – cooling or auxiliary losses, which result from the use of cooling equipment such as fans and

Housed in VaultsNetwork transformers, which are distribution transformers serving grid and spot networks, are large - sized three - phase units.According to ANSI C57.12.40 - 1982, network units are typically categorized as vault - type or subway - type:Vault - type transformers: Suitable for occasional submerged operation.Subway - type transformers: Suitable for frequent or continuous submerged operation.Network transformers are also employed in buildings, typically in the basement. In such case

What is Capacitive Voltage Transformer?Definition: A capacitive voltage transformer (CVT), also known as a capacitive potential transformer, steps down high - voltage input signals to provide low - voltage signals that can be easily measured by measuring instruments.The capacitive potential divider, inductive element, and auxiliary transformer are the three main components of a capacitive potential transformer.Why is a Capacitive Voltage Transformer (CVT) Needed?When measuring high voltages abov

Very Fast Transient Over voltage(VFTO) wave common characteristics in HV& EHV GISSteep wavefront, with a rise time typically ranging from 2 to 20 nanoseconds: When restriking occurs in the contact clearance of a disconnector, the arc - reignition process is extremely rapid. As a result, the voltage waveform injected into the power grid exhibits a very high ascending or descending steepness.Theoretically, the amplitude of Very Fast Transient Overvoltage (VFTO) can reach up to 3.0 per - unit.

As a personnel who has long been involved in the operation and maintenance projects of power distribution equipment, I deeply recognize that distribution transformers, situated in the complex power distribution ecosystem, continuously endure mechanical stresses from electromagnetic forces caused by electrical faults, vibrations during transportation, and various environmental forces. To ensure their mechanical integrity, systematic inspections are indispensable. Different from electrical and the

In the realm of power distribution,distribution transformersshoulder the critical task of stepping down voltage for end-users. Amidst electrical and mechanical demands, their thermal performance dictates operational lifespan and grid stability. Rigorousinspectionof thermal attributes—from temperature rise to heat dissipation—is paramount. This article explores how thermal performanceinspections safeguarddistribution transformersagainst overheating, a silent yet pervasive threat.1. The Vital Role