MIDAS micro 2883 Power Factor Tester

Safe operation with interlock, emergency stop, safety checks and HV ground surveillance

Three operating modes: basic, guided, advanced

Rugged case with included accessories bag

Highest accuracy

Advanced interference suppression

Ability to measure tan delta of insulating oil quickly on site with the 6835 Portable Oil Test Cell

Bushings provide an insulated entrance for an energized conductor into an equipment tank or chamber. Whether they are capacitively graded or bulk type (solid throughout), installed or spare, you can perform overall capacitance test, center conductor to tap test, tap insulation test and hot collar test with the MIDAS micro 2883.

The dissipation factor or power factor test for distribution transformers and power transformers is a very comprehensive test for detecting moisture, carbonization, and other forms of contamination of windings, bushings, and liquid insulations for single-phase, three-phase and autotransformers. The scope of the power factor test for transformers is to determine the capacitance (insulation) between the individual windings and between the windings and ground as per IEEE C57.12.90 and IEC 60079-1 standards.

Shunt reactors are used in HV systems to limit over-voltage surges associated with long transmission lines. The shunt reactor compensates the capacitive generation on power lines to avoid non-controlled voltage rise especially on lightly loaded lines. Similar to a transformer, power factor and capacitance testing are vital for assessing the health of insulation and detecting potential degradation.

Current transformers (CTs) convert high transmission line current to a lower, standardized value to be handled by instrumentation. The measures are used for network control, protection and revenue metering. Substation current transformers have voltage ratings from several kilovolts up to the highest system voltages now in operation and are typically oil-filled but are also available as a dry type version, normally filled with SF6. The power factor test helps assess the insulation’s integrity and can detect early signs of deterioration, like moisture or contamination.

A capacitor voltage transformer consists of a capacitor voltage divider and an inductive/electromagnetic unit. The electromagnetic unit includes a transformer and a reactor whose inductance is adjusted in resonance to the equivalent capacitance of the voltage divider. The secondary voltage of the electromagnetic unit is proportional to the primary voltage and differs in phase from it by an angle which is approximately zero.

Dissipation-factor tests on cables are useful to indicate general deterioration and/or contamination. An increase in dissipation-factor with test voltage may be an indication of a serious general condition of corona in the insulation. With the MIDAS micro 2883 you are able to test several different types of cables such as single-conductor with shield or sheathed, single-conductor without shield or sheath, 3 phase unshielded enclosed in a common metallic sheath, 3 phase individually shielded and 3 phase unshielded.

Capacitance tests on power-factor correction, surge or energy storage capacitors test the insulation quality of the capacitor. Typically, capacitors are built using a series of single capacitor modules. If one module shows a problem, the result will affect average or overall capacitance of all connected modules. So, a small change in the measured total value could show a bigger problem in a single module.

Power factor and capacitance testing are crucial diagnostic methods for assessing the insulation condition of circuit breakers. These tests help detect deterioration, contamination, and other issues that can compromise the breaker’s reliability and safety. For insulation measuring purposes high voltage circuit breakers can be classified into two groups. Live tank breakers whose interrupting chamber is on HV potential and dead tank breakers whose interrupter chamber is accommodated in an earthed metal housing.

The surge arrester power loss test can reveal the presence of moisture, salt deposits, corrosion, cracked porcelain, open shunt resistors, defective pre-ionizing elements and defective gaps which hinder the lightning arrester’s main function. Lightning (or surge) arresters protect the electrical system by neutralizing discharge transient currents which are the result of lightning and switching. If a discharge transient current occurs it should close to providing a safe path for the excess electrical charge to flow to ground. Once the surge has passed and the voltage returns to safe levels, the arrester must stop conducting and return to its standby mode to prevent the flow of normal system power through it.