Partial discharge testers with surge test

SCHLEICH partial discharge testers SCHLEICH surge test partial discharge analysis in a powerful test concept that can be used to assess the insulation quality of electrical windings—especially in motors, generators, transformers, and coils.

The surge test electrical loads such as those caused by converter operation, switching operations, or voltage spikes. To do this, a charged surge capacitor with a very short voltage rise time is connected to the device under test DUT). The aim is to detect insulation weaknesses, winding short circuits, or manufacturing defects at an early stage.

At the same time, partial discharge (PD) is detected and evaluated. Partial discharges are local insulation breakdowns that do not immediately lead to a complete short circuit, but cause long-term damage to the insulation. The measurement is carried out in accordance with standards, is highly sensitive, and frequency-selective.

Partial dischargePD test, also known asPD test," is surge test the most important and meaningful testing methods available today, along with surge test , for reliably detecting problems in windings. It mercilessly reveals a wide range of insulation, material, and production defects.

Why partial discharge testing is so important.

Electric motors, generators, rotors, stators, transformers, valve coils, windings of all kinds, and much more can only be operated safely and durably if they have high electrical insulation strength, good material quality, and flawless manufacturing. Poor insulation can quickly lead to total failure.

Partial discharge testing in combination with surge test you surge test determine the quality of the winding and the insulation system both inside the winding and laminated core .

SCHLEICH has developed SCHLEICH comprehensive portfolio of testing devices ranging from 1,000 to 15,000 V to cover virtually all areas of winding material testing.

However, partial discharge testing cannot replace all known testing methods. For this reason, testing equipment or automatic testing machines usually combine different testing methods. The starting point is always the surge test, ideally in combination with the PD test.

Where the device under test is device under test .

The surge test the"deep look into the winding":

• within the winding from turn to turn
• from winding to winding
• from phase to phase
• from winding to laminated core

This does not high voltage test with a high voltage test

The high voltage test achieve such a high level of testing depth. The ultimate solution is a combination of surge voltage and partial discharge testing.

These faults are covered by the partial discharge test in addition to the surge test .

• Inadequatefrequency convertercompatibility
• Insufficient insulation distances
• poorly positioned phase separators
• insulation weaknesses
• enameled copper wire fault
• Spacing problems between windings with high potential differences
• Phase spacing problems
• Distance problems withlaminated core
• Spacing problems between layers
• …

How does partial discharge testing work technically?

The surge tester basically surge tester a high-voltage pulse with a very high edge steepness.

To do this, the surge capacitor device in device is voltage to the desired voltage . As soon as the TEST VOLTAGE is TEST VOLTAGE , the test device switches the charged capacitor to the winding to be tested via a very fast semiconductor switch. This results in an oscillating circuit consisting of the inductance test object and the charged capacitor. The impulse response at the oscillating circuit is initially a very steep voltage rise, followed by the typical voltage curve in the form of a damped oscillation.

If defects of the type described above are present, applying higher test voltages will not necessarily result in a high-energy lightning discharge. However, partial, low-energy discharges may occur at the damaged location when the partial discharge onset voltage is exceeded. These are neither visible nor audible. However, they often lead to total failure of the insulation within a short time.

Partial discharge is also referred to as pre-discharge, as it occurs even at low test voltages. It is therefore a kind of "harbinger" of impending damage.
This is precisely what makes partial discharge testing so interesting and important.

This is how the partial discharge test is performed.

Partial discharge is a side effect of high voltage test alternating current (AC) and/or surge test.

Since every electrical discharge emits discharge electromagnetic wave, partial discharge can be easily detected with an antenna. This is ideal for open windings, i.e., whenever the winding is not enclosed in metal, as is the case with a fully assembled Motor generator.

Since partial discharge also spreads to the connection cables of the test object, partial discharge can alternatively be measured with a coupling module in the case of windings that are completely shielded with metal.

The requirements for a partial discharge tester for winding systems.

SCHLEICH partial discharge testers have the following features:

• standard-compliant testing
• Surge voltage pulses with high voltage slope
• Very fast measurement technology with high resolution
• Determination of the
  • insertion voltage
  • repeated insertion voltage
  • repetitive suspension voltage
  • breakdown voltage
• fully automated analysis
• Fully automatic switch-over the various winding connections of the test object
• Development, production, and service – Made in Germany

SCHLEICH are based on over 30 years of experience and pioneering work. From the very beginning, the measurement technology was not analog but always digital. Only the most modern technologies are used.

How to find the right partial discharge tester.

If you onlyrun partial discharge tests on your device under test , a single test device is the right choice. This includes the surge test a starting point for determining partial discharge.

device under test the device under test requires device under test tests, we recommend our combination testers/multifunction testers. These can be supplemented with additional test methods such as partial discharge, high voltage test (plus partial discharge if required), ohmic Resistance test, rotating field test, etc. The fully automatic test method switching ensures that no test leads need to be device under test reconnected to device under test during the test.

Thanks to the intuitive and convenient operation of our surge voltage testers, every test is quick, precise, and cost-effective.