Transformer Excitation Characteristic Tester

The MOEORW-WHF10 is a full-function offline testing device designed for protective and metering transformers up to 35kV. It integrates CT excitation (volt-ampere) characteristic testing, PT excitation characteristic verification, ratio and polarity determination, AC withstand voltage testing, primary current injection, and core demagnetization into a single unit - eliminating the traditional reliance on voltage regulators, current boosters, multimeters, and other separate equipment. Whether used for on-site commissioning by power engineering companies or for routine maintenance by inspection teams, this transformer comprehensive tester (also known as a CT/PT Analyzer) provides a complete winding characteristic diagnostic solution as a standalone instrument, enabling users to obtain traceable, standardized data in the shortest possible time.

The product strictly complies with national standards GB 1207-2006 (electromagnetic voltage transformers) and GB 1208-2006 (current transformers). All testing algorithms and error judgment logic are synchronized with power industry acceptance regulations. Factory calibration is performed at 23℃±5℃, with excitation measurement accuracy reaching ≤0.5% (i.e., 0.3% of reading + 0.2% of range), and annual stability better than 1%. This accuracy level means that key parameters such as knee-point voltage and limit factor coefficient obtained from this Excitation Characteristic Tester in field environments can be directly used as valid raw data for completion reports or preventive test records, without requiring secondary conversion or manual correction.

CT/PT Excitation (Volt-Ampere) Characteristic Testing

Output voltage range: 0～1200V, maximum output current 20A, covering the saturation region of most windings up to 35kV.

Automatically plots the volt-ampere characteristic curve with simultaneous marking of knee-point voltage and current values - no manual plotting required.

PT mode supports voltage multiple adjustment (1.2～3.5×), facilitating over-excitation characteristic inspection for voltage transformers of various specifications.

Built-in 5% and 10% error curve calculation module that automatically determines whether the protective winding is qualified based on nameplate parameters (e.g., the limit factor in 5P10).

Ratio & Polarity Determination

CT ratio measurement range: ≤5000A/1A (or 25000A/5A), accuracy ≤0.5%.

PT ratio covers 3～500kV classes, secondary side compatible with multiple taps: 100V, 100/√3, 100/3, 150V, 220V.

Automatic identification of terminals with the same polarity. When same-color terminals (P1 with S1, A with a) are connected, the polarity result is directly displayed as "subtractive polarity," consistent with the sampling logic of mainstream domestic protection devices.

Primary Current Injection & AC Withstand Voltage

Primary current injection output 0～600A, with current below 200A sustainable for 5 minutes, suitable for verifying the integrity of secondary circuits of high-ratio current transformers.

AC withstand voltage setting 0～1200V. When leakage current exceeds the limit, the output automatically returns to zero and displays "UNQUALIFIED," preventing weak insulation points from sustaining prolonged high-voltage stress.

Data Management & Report Output

Built-in storage capacity of 3,000 test records, retained after power-off.

Equipped with a micro thermal printer for on-site printing of curves and data lists.

Supports USB drive data transfer, and with the PC companion software (Windows-compatible), can generate Word-format inspection reports with one click - no manual data entry required.

Scenario 1: Acceptance Tests for Newly Built Substations

At a newly built 110kV substation, commissioning teams need to perform comprehensive excitation characteristic, ratio, polarity, and insulation withstand tests on dozens of CT/PT units. With the MEFA-V, test personnel need only one wiring connection and one parameter setup - the device automatically handles voltage/current boosting, data acquisition, and knee-point calculation, reducing testing time per winding from 30 minutes (traditional method) to under 5 minutes. Weighing ≤22kg, the unit can be carried and moved by a single person, making it particularly suitable for parallel operations across multiple bays during peak installation periods. In this scenario, this Excitation Characteristic Calibrator fully demonstrates its core value of high efficiency and portability.

Scenario 2: Preventive Testing During Power Plant Overhauls

The annual overhaul window for power plants is extremely limited, demanding the highest time efficiency. The built-in intelligent prompt functions of this Transformer Excitation Characteristic Tester (such as wiring verification and circuit breaker open warning) effectively prevent retesting caused by novice misoperations, ensuring every minute is spent on actual measurement. The demagnetization function can be executed immediately after characteristic testing without rewiring, helping maintenance personnel restore equipment to serviceable condition in the shortest time.

Scenario 3: Factory Acceptance and Spot Inspections at Transformer Manufacturing Plants

For transformer manufacturers, this CT/PT Analyzer can serve as standard equipment at factory inspection stations. Its automatic error curve calculation function enables rapid comparison of batch product consistency. The 3,000-record storage capacity combined with USB export facilitates monthly data aggregation by quality departments and trend tracking of excitation characteristics for each product.

Scenario 4: University Electrical Laboratories & Research Institutions

In electrical engineering laboratories, this Ratio & Polarity Tester with its excitation characteristic verification function can serve as a teaching demonstration platform, visually displaying core saturation processes, knee-point formation mechanisms, and error curve derivation logic. Its graphical interface and rotary controller interaction design lower the threshold for students to understand abstract theories.

Scenario 5: Third-Party Testing Institutions (CMA/CNAS Laboratories)

Third-party testing institutions have stringent requirements for data traceability and report standardization. The MEFA-V's excitation data list displays voltage/current correspondence point by point. Combined with the standardized Word report exported via PC software, it completely preserves original test data and calculation processes, facilitating auditor traceability and significantly improving the efficiency and credibility of report issuance. This Transformer Comprehensive Tester has become standard equipment in multiple CMA-accredited laboratories.

Advantage 1: Balanced Power Output Capability and Protection Mechanisms

The device employs a wide-range linear power amplifier module internally - unlike the traditional voltage regulator + step-up transformer combination - achieving output waveform distortion of less than 1%, ensuring true consistency of all points on the excitation characteristic curve. Additionally, the panel features an independent overcurrent protection (power) switch, while the software incorporates voltage/current upper-limit cut-off protection, forming a dual hardware + software safety guarantee. Even in the event of inter-turn breakdown in the tested winding, the device can cut off output within microseconds, protecting internal power components from damage.

Advantage 2: Practical Error Curve Algorithm

The error curve is not generated by simple point-plotting but is strictly calculated according to the composite excitation method principle specified in GB/T 16847 (IEC 60044-1). As a professional Excitation Characteristic Tester, users simply input the rated burden, secondary DC resistance, and limit factor coefficient, and the device automatically generates the relationship diagram between permissible secondary burden and current multiples. For example, when test data shows that the permissible burden at 10 times rated current exceeds the nameplate value (e.g., 20VA corresponding to 20Ω), the system directly determines the winding as qualified. This logic has been verified through extensive field comparison tests, with deviation from standard transformers less than 1%.

Advantage 3: Full-Chinese Intelligent Prompt System

To address potential wiring oversights in the field, this Transformer Comprehensive Tester performs port impedance pre-detection before starting any test. If the secondary winding is incorrectly connected to S1/S2 instead of K1/K2 terminals, the screen will pop up a clear Chinese error message and abort the voltage boost, preventing erroneous data or even damage to the tested object due to wiring confusion. This feature is particularly user-friendly for non-professional operators and significantly reduces training costs. (Note: English interface and prompt language options are available upon request.)

Advantage 4: Low Temperature Rise & Long-Life Design

Under rated output conditions, the temperature rise of main power components is controlled within 40℃ (at 23℃ ambient temperature), achieved through efficient cooling air ducts and aluminum heat sink substrates. Based on factory accelerated aging tests, as an industrial-grade CT/PT Analyzer, its Mean Time Between Failures (MTBF) exceeds 50,000 hours, ensuring continuous operational reliability during peak grid maintenance periods.