How to Choose a High-Current Booster? These Parameters Must Match

Recently, a colleague asked me, "When buying a high-current booster, the salesperson quoted a bunch of parameters, such as rated current, measurement accuracy, waveform distortion... I don't know which one to focus on." This article will help you clarify the core logic of selection from the perspective of practical use.

First: confirm the maximum current required by the test sample

Thermal relays, circuit breakers, and air switches each have different rated current levels. The upper limit of your current booster's output must cover the test multiple of the tested object. For example, when calibrating a thermal relay rated at 100A, it is usually necessary to apply 3 to 6 times the overload current, which is 300 to 600A. Choosing a 200A single-phase current booster is clearly insufficient. If using a three-phase model, some designs support three-phase parallel output, effectively extending the upper limit of single-channel current.

Second: check whether three-phase independent adjustment is required

Single-phase current boosters can only test phase by phase, resulting in low efficiency; three-phase high-current generators can output all three phases (ABC) simultaneously, and can also individually adjust one phase to simulate phase loss faults. For testing scenarios that require verification of the three-phase unbalanced operation characteristics of protection devices, a three-phase model is a better choice.

Thirdly, don't overlook the precision requirement

Power system tests generally require an accuracy level of 0.5 or above. High-quality models use 0.2S-level materials, and the actual measured accuracy can reach around 0.3 level. If you are engaged in the verification of metering equipment or transformers, the accuracy requirements are even higher and need to be confirmed separately.

Fourth: Distinction between short-term and long-term working systems

Ordinary high-current current risers are designed for short-duration tests (such as 5 minutes), suitable for daily circuit breaker characteristic tests. If a temperature rise test (long-duration operation from 30 minutes to 24 hours) is required, it is imperative to choose a specialized temperature-rise type high-current generator. The structures and heat dissipation designs of the two are significantly different and cannot be interchanged.

Fifth: Overall size and on-site portability

Due to limited space for on-site maintenance at substations, opting for an integrated design that is compact in size and comes with a random test cable can greatly facilitate the process. Some new three-phase current boosters have a volume that is only 30% to 70% of similar products. For engineers who frequently travel for testing, weight and external dimensions are also practical considerations.

Check these five points against your own usage scenarios, and you can basically lock in the appropriate model.

HZDL-200III  3 Phase Primary Current Injection Tester