Un produttore nazionale di locomotive elettriche ha stretto una partnership con DEMIKS per garantire la sicurezza delle locomotive elettriche attraverso test ad alta tensione.

In the field of electric locomotive manufacturing, ensuring the insulation performance of high-voltage electrical components is crucial for the safe and stable operation of locomotives. Recently, a subsidiary locomotive manufacturing plant of CRRC Electric Locomotive Co., Ltd. has partnered with DEMIKS Power to introduce advanced apparecchiature di prova ad alta tensione, safeguarding the insulation safety of electric locomotives. The DEMIKS high-voltage testing equipment used in this project demonstrates outstanding performance in power frequency withstand voltage testing. This equipment can accurately test key high-voltage electrical components such as pantographs, traction transformers, and high-voltage cables. Taking the pantograph as an example, it can simulate test voltages up to 50kV, far exceeding its normal operating voltage. Through a continuous one-minute withstand voltage test, it can effectively detect potential insulation problems in parts such as carbon sliding plates and insulators. As the “power heart” of the electric locomotive, the insulation performance of the traction transformer is of paramount importance. DEMIKS testing equipment sets test voltage standards of 75kV and 1800V for traction transformers, specifically for the primary winding to secondary winding and to ground, and the secondary winding to ground. Testing is strictly performed according to industry standards such as GB/T 25122 to ensure the insulation reliability of transformers under complex operating conditions. For 25kV high-voltage cables, the equipment uses a test voltage of 62.5kV to comprehensively test the insulation between conductors and between conductors and ground, leaving no potential for insulation failure unchecked. DEMIKS high -voltage testing equipment not only accurately simulates extreme voltage conditions but also possesses extremely high detection sensitivity. Its leakage current monitoring accuracy reaches the μA level, enabling the early detection of subtle signs of insulation degradation. Simultaneously, the digital control console enables precise control of the voltage boosting rate and automatic recording of test data, significantly improving testing efficiency and data accuracy.

Migliori DEMIKS power frequency withstand voltage test system is a type of high-voltage power testing equipment. It is primarily used to test the withstand voltage performance of electrical equipment (such as the insulation components of locomotives) and verify the insulation reliability of the equipment under rated voltage. This type of equipment typically consists of a control console (responsible for parameter setting and control) and a trasformatore di prova (responsible for voltage boosting), and is a commonly used testing tool in industries such as power and railways.

As an electric locomotive manufacturer, CRRC Group purchases power frequency withstand voltage devices primarily for three core needs: production compliance, product safety, and quality control.

1. To meet the mandatory standards of the railway industry, the high-voltage electrical components of electric locomotives (such as pantographs, traction transformers, and high-voltage cables) must pass the power frequency withstand voltage test. This is a mandatory testing procedure in the railway industry (such as GB/T 25122, EN50155, etc.) . Only by passing the withstand voltage test can the product obtain CRCC and other access certifications and be qualified to leave the factory.

2. , which ensures the safe operation of locomotives , can simulate extreme voltage conditions and detect hidden defects such as insulation layer damage, loose wiring, and internal air bubbles. This prevents short circuits, leakage, and even fires caused by insulation failure during locomotive operation, and is directly related to the safety of trains and personnel.
3. Controlling production quality and managing the entire life-cycle, from component delivery to vehicle acceptance, the withstand voltage test is a key step in quality control. At the same time, during subsequent locomotive maintenance, this device is also needed to detect problems such as insulation aging and moisture, ensuring the long-term reliable operation of the equipment.

The power frequency withstand voltage test of high-voltage electrical components in electric locomotives is a core testing step to verify their insulation performance. The testing focus and procedures differ for different components. The following is a detailed breakdown:

I. Core Principles of Power Frequency Withstand Voltage Test

Utilizzando a power frequency withstand voltage device (control console + test transformer) to output a power frequency sinusoidal voltage several times higher than the rated voltage of the component (usually 1.5 to 2 times the rated voltage), and continuously applying it for a certain period of time (usually 1 minute), observe whether the component exhibits problems such as insulation breakdown, flash-over, or excessive leakage current, thereby determining the insulation reliability.

II. Key Points for Testing Different High-Voltage Components

1. Pantograph

• Posizioni di prova : Insulation between the pantograph’s carbon sliding plate, insulator, and conductor rod.
• tensione di prova : Usually twice the rated grid voltage of the locomotive (for example, for a locomotive with a grid voltage of 25kV, the test voltage is 50kV).
• Precauzioni : During the test, the pantograph must be raised to the working position to avoid mechanical structures obstructing the insulated parts, and the leakage current should be monitored (generally not exceeding 100μA).

2. Traction transformer

• Sito di test :

• Insulation between the primary winding and the secondary winding, and between the primary winding and ground.
• Insulation of secondary winding to ground
  • tensione di prova :
• Primary side: According to the grid voltage level (for a transformer with a 25kV grid voltage, the primary side withstand voltage to ground is generally 75kV).
• Secondary side: twice the rated voltage of the traction motor (for example, for a 900V secondary side, the withstand voltage is 1800V).
  • Precauzioni : Before the test, disconnect the transformer from other components and fully discharge the windings to avoid residual charge affecting the results.

3. High-voltage cables

• Posizioni di prova : Insulation between cable cores and insulation between cable cores and ground.
• tensione di prova : 2.5 times the rated voltage of the cable (for example, for a 25kV high-voltage cable, the withstand voltage is 62.5kV).
• Precauzioni : Before the test, check that the cable terminals are properly sealed to prevent moisture absorption; after the test, discharge each phase sequentially to prevent the risk of electric shock.

III. Test Execution Procedure (Taking a Whole Vehicle as an Example)

1. Fase di preparazione : Disconnect the high-voltage system from the low-voltage system of the locomotive and grounding protection; check whether the grounding and wiring of the withstand voltage device are correct.
2. Voltage ramp-up phase : Slowly increase the voltage to the test value (the ramp-up rate is generally ≤0.5kV/s), and monitor the leakage current changes during this period.
3. Holding voltage stage : Maintain the test voltage for 1 minute and observe for any abnormalities such as breakdown or flashover.
4. Voltage reduction phase : After slowly reducing the voltage to 0, fully discharge the components (discharge time ≥ 5 min).
5. Recording stage : Fill in the test voltage, time, leakage current and other data, and determine whether it is qualified.

In past projects, a well-known railway equipment manufacturer saw a 30% reduction in product failure rates due to insulation issues after using DEMIKS high-voltage testing equipment, significantly improving product quality and market reputation. This locomotive manufacturer, by introducing the equipment this time, is also expected to achieve significant results in improving product quality and ensuring operational safety, further consolidating its leading position in the rail transit equipment field. Through cooperation with DEMIKS Power , the company has achieved technological upgrades in the high-voltage testing of electric locomotives, laying a solid foundation for producing safer and more reliable electric locomotives.