Special Testing

SFRA TEST :
Sweep Frequency Response Analysis (SFRA) is a powerful and sensitive method to evaluate the mechanical integrity of core, windings and clamping structures within power transformers by measuring their electrical transfer functions over a wide frequency range. SFRA is a proven method for frequency measurements.

SFRA analysis can detect problems in transformers such as:

• winding deformation – axial & radial, like hoop buckling, tilting, spiraling
• displacements between high and low voltage windings
• partial winding collapse
• shorted or open turns
• faulty grounding of core or screens
• core movement
• broken clamping structures
• problematic internal connections

DCRM TEST :
Circuit Breakers are one of the critical "safety-valves" of electrical systems, Effective circuit breakers requires well-organized DCRM accurate testing. The ability to accurately compare circuit breaker tests with previous test results is essential. DCRM Comparison can provide a clear picture of any deviations and changes, thereby indicating whether or not the circuit breaker should be kept in operation or taken out of service for further investigation.

• Universal Circuit Breaker Operational Analyser to test all types of CBs - LV, HV, EHV & UHV.
• Quick performance check of CB by measuring C, O, C-O, O-C & O-C-O timings.
• Dynamic Contact Resistance Measurement for condition monitoring of the contacts without opening the interrupter.
• Analysis of Travel Characteristic with customized Travel Transducer cum Fixtures.
• Saves down time & number of operations of CB by testing all the critical performance parameters of all the poles / breaks in a single shot.
• Healthiness of Auxiliary contact by measurement of Auxiliary contacts timings.
• Healthiness of Close / Trip coils of all three poles monitored simultaneously.
• Laptop operated. Results are immediately displayed on the screen.
• Contact Resistance of main contacts.
• Useful to shift maintenance schedule form Time based to Condition based.
• Work reliably under live EHV switchyard conditions ensuring operator's safety and repeatability of results.

HV TAN DELTA
Tan Delta is a a diagnostic test conducted on the insulation of cables and windings, Bushing, Oil. It is used to measure the deterioration in equipments. It also gives an idea of the aging process in the cable/windings and enables us to predict the remaining life of the cable / windings. It is alternatively known as the loss angle test or the dissipation factor test
A fully automatic 12-kV insulation power/dissipation factor (tan delta) test set is used for Diagnostic test .Inser Hitech has been providing insulation diagnostic test procedures to the power market since 2000 and we now offer the latest technology available on the market today. With automatic and manual operations we work for even the toughest work environments. Enhanced safety features reduce the risk of catastrophic failure of equipment and prevent injury to personnel.

Numerical Relay Test:
The protection functions of the relay and the transient currents and voltages are still the same, but it is the present state of technology that offers new possibilities and makes the number of functions in the relay more complex. It is generally agreed that testing numerical protection should be different from older techniques. Some basic aspects of numerical protections generally address this:

• The data acquisition and processing is totally different from older techniques. It is not only characterised by components but also by software algorithms. Moreover, non-analytical processing systems could be used that are based on Artificial Intelligence techniques (Neural networks, Expert systems, etc.).
• Input/output logic is often programmable. This introduces a new degree of flexibility with the consequence that additional, specific tests need to be performed on the protection scheme as a whole.
• The capacity of the microprocessor-based systems is rapidly increasing and generally precludes the need for single function relays. Protection is evolving to a multifunction box that affects the adequacy of the test programme. The function complexity of numerical relays has reached a level where it is impossible to test every performance possibility. Consequently, the difference between the function performance and scheme performance is increasing.
• Self-supervision is a basic characteristic of numerical protection. It should allow a decrease in periodic testing, and eventually eliminate it, if the protection supervision addresses the scheme as a whole. Conversely, it also introduces the question of testing the self-supervision itself and of the necessity to have an understanding of its depth.
• Digital communication ports introduce a new way for protection technology to communicate with the environment. The validation of this communication media is also a new area in protection testing.
• Numerical relays are very suitable for adaptive functions. Conditional changes should be considered in the tests.
• The first numerical developments have been subject to many software upgrades. This has created some concern about validating software evolution independent of hardware.

CT / PT Analyser Kit :



MULTI FUNCTION SYSTEM FOR TESTING:
CURRENT, VOLTAGE AND POWERTRANSFORMERS
The following table lists the tests that can be performed on Current transformers (CT), Voltage Transformers (VT) and Power Transformers (PT).

1 CT Ratio, polarity and burden, Current mode
2 CT Burden; secondary side
3 CT Excitation curve
4 CT Winding or burden resistance
5 CT Voltage withstand
6 CT Polarity by impulses
7 CT Ratio, Voltage mode
8 VT Ratio; polarity
9 VT Burden, secondary side
10 VT Ratio, electronic transformers
11 VT Voltage withstand
12 VT Secondary over-current protection
13 PT Ratio per TAP
14 PT Resistance of TAP Changer contacts
15 GR Earth resistance
16 GR Soil resistivity


CPC 100 OMICRON



Universal testing device for electrical diagnostics

Electrical tests on transformers, current transformers, voltage transformers, grounding systems, lines and cables, and circuit breakers can be performed with the CPC 100.

The CPC 100 is the base for multiple accessories. These facilitate further applications, such as tan delta measurements, as well as line and ground impedance measurements.

The patented test system replaces several individual testing devices and offers new, innovative testing methods.


Applications

Current transformers (CT)	Voltage transformers (VT)
Ratio, burden and polarity Phase and magnitude error Excitation curve Winding resistance Secondary burden Dielectric withstand voltage (2kV AC) CT circuit continuity	Ratio, burden and polarity Phase and magnitude error Excitation curve Winding resistance Secondary burden Dielectric withstand voltage (2kV AC) VT circuit continuity
Transformers	Lines and cables
Ratio Winding resistance Tap changer test Excitation current Short circuit impedance	Impedance (k-factor) Transformer coupling
Grounding systems	Circuit breakers
Ground impedance Step and touch voltages	Contact resistance