Yadda ake cikakken bayanin photovoltaic transformers ta shafi?

1. Karkashin da Muhimmanci na Tattalin Photovoltaic Transformers

A kan ina jin da shugaban kimiyyar tattalin enegiya masu zaman, ina sanin cikakken gyara da tushen photovoltaic transformers: Inverter - output AC ya shiga abubuwa da dama da tsawon 5th/7th - order odd harmonics, da PCC harmonic current distortion ya kai 1.8% (kafin yana da muhimmanci da hankali a lokacin yawan zafi), wanda ya haɗa da hoton gyaran da ke kusa da kuma lafiya da ke kusa. Tattalin photovoltaic sun yi amfani da TN - S grounding, wadannan ya ba da kyau a nemi N - phase output daga tarafin biyu don bincike wasu maimaituka. A cikin yanayi, suka da kyau a duba damuwar sahar 60°C, fura mai salt da ke gida, da kuma EMI masu tattalin enegiya.

Wadannan muhimman irin tattalin ya ba da muhimmanci ga tattaunawa: Duk da tattaunawa masu zamantaka kamar DC resistance, voltage ratio, insulation, da withstand voltage tests, za su iya yin tattaunawa masu harmonics (Fluke F435 for THD), temperature rise monitoring (infrared imagers), grounding system checks (four - terminal method for ≤0.1Ω contact resistance), da short - circuit impedance testing. Yadda aka ambaci shine in bayyana aiki da dalilin tattalin enegiya game da kare kusa da hankali, thermal, da muhimman tushen grounding.

2. Tattaunawa Masu Zamantaka da Zabubbukan Tattalin Don Photovoltaic Transformers
2.1 Tattaunawa na DC Resistance

Wannan tattaunawa mai muhimmanci ya samun koyar inter - turn short circuits ko koyar windings. An yi amfani da four - terminal method don bincike interference daga line resistance, da kuma misalai sun hada da power-off discharge, winding cleaning, temperature measurement, current selection (1A/10A), da kuma temperature correction. ZSCZ - 8900 DC resistance tester (accuracy: 0.2%±2μΩ, resolution: 0.1μΩ) ya ba da muhimmanci ga tattaunawa masu sakamako. Za su iya kara koyar da standards/historical data; waɗannan zabuku masu yawan muhimmanci suna nuna ainihin koyar - kamar wanda aka samu da koyar winding contact da ta ƙasa a kan tattaunawa na DC resistance da kuma ana kammala a baya.

2.2 Tattaunawa na Voltage Ratio

Wannan ya tabbatar da cewa tsawon windings ya danganta da takardun da ake rubuta don bayyana aiki da dalilin tattalin a lokacin da ake magance. Dual - voltmeter method ya kula da tsari da kuma primary/secondary voltages a lokacin da ba ake magance, idan an yi amfani da voltage ratio bridge method ya ba da sakamako masu muhimmanci. Misali, an samu da ainihin koyar da ta ƙasa a kan low - voltage output daga 800V/400V transformer, wanda ta faru ne saboda high - voltage side open circuit, a kan tattaunawa na voltage ratio.

2.3 Tattaunawa na Insulation Performance

• Tattaunawa na Insulation Resistance: Da amfani da MI - 2094H megohmmeter, ya kula da tsari da insulation resistance daga windings da kuma daga windings zuwa core (required ≥300MΩ).

• Tattaunawa na Withstand Voltage: Apply 2× rated voltage for 60 minutes to check for breakdown. Ensure power is off, disconnected from live equipment, and surfaces are clean before testing.

2.4 Tattaunawa na Short - Circuit Impedance

Volt - ampere method ya kula da tsari da tolerance masu short - circuit: Tarafinsu ita ce ta fi sani, da kuma ake magance test voltage a kan tarafin biyu don drive rated current through windings, measured by a CS - 8 impedance tester. A change >±2% from the factory value may indicate winding deformation. Note: Test current should be controlled at 0.5% - 1% of rated current to avoid waveform distortion.

2.5 Tattaunawa na Temperature Rise

Ba da full - load operation, measure temperatures of windings, core, and casing using thermometers or infrared thermometers. Temperature rises should be ≤60K for oil - immersed transformers and ≤75K for dry - type transformers. A dry - type transformer operating in a 60°C environment that maintained a temperature rise within 65K extended its service life effectively.

2.6 Tattaunawa na Grounding System

The four - terminal method measures grounding continuity to avoid misjudgments from the two - terminal method. Common faults include rusted connections or plastic washer misuse, requiring regular inspection. Four - terminal ground resistance testers ensure measurements meet the 0.1Ω standard.

2.7 Harmonic Detection

A unique test for photovoltaic systems, using Fluke F435 at the PCC to detect harmonics up to the 50th order (focusing on 5th/7th orders). Results must comply with GB/T 14549 - 93, providing data for equipment optimization.

3. On - site Testing Procedures and Safety Specifications for Photovoltaic Transformers
3.1 Pre - testing Preparation

Develop detailed plans specifying project information, testing items, and equipment lists (including high - precision power analyzers, power quality testers, infrared thermal imagers, etc.). Check equipment integrity and power voltage (220V&plusmn;10%), and monitor environmental conditions - such as irradiance &ge;700W/m&sup2;, irradiance variation <2% in the preceding 5 minutes, no strong winds or clouds - to ensure test accuracy.

3.2 Electrical Connection Inspection

Use a phase volt - ampere meter to verify inverter output polarity matches the transformer's primary corresponding terminal, preventing circulating current losses. Inspect cable connections for tightness. For oil - immersed transformers, check oil level and color; for dry - type transformers, verify cooling fans operate normally.

3.3 Insulation Resistance Test

With power off, use a megohmmeter to test high/low - voltage windings and grounding, recording 1 - minute stable values. A sudden resistance drop indicates insulation issues. Detailed test reports must be compiled post - testing.

3.4 AC Withstand Voltage Test

Connect the withstand voltage device's output to test points, set parameters to 2&times; rated voltage, gradually increase voltage while monitoring for breakdown, and maintain for 60 minutes before reducing voltage.

3.5 Load Test

Measure output voltage, current, and power under full - load operation to calculate efficiency and voltage regulation rate, while monitoring temperature rise. Increase load current gradually and record parameter changes for analysis.

3.6 Short - Circuit Impedance Test

Apply voltage to the high - voltage side with the low - voltage side shorted (using wires with sufficient cross - section). Control test current at 0.5% - 1% of rated value and correct results for temperature (75&deg;C for oil - immersed, 120&deg;C for dry - type) to avoid misjudging winding deformation.

3.7 Harmonic Detection

Use a power quality analyzer at the PCC to monitor odd - order harmonic content and calculate THD, ensuring compliance with national standards for safe operation in harmonic environments.