DL/T 294.4-2019 in English
VALIDSpecification for equipment of de-excitation and overvoltage protection for generators—Part 4:De-excitation capacity calculation
- Issued on:2019-06-04
- Implemented on:2019-10-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
Price(USD)：
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$165.00
$165.00
| Standard No: | DL/T 294.4-2019 |
| Document status: | VALID |
| Title in English: | Specification for equipment of de-excitation and overvoltage protection for generators—Part 4:De-excitation capacity calculation |
| Title in Chinese: | 发电机灭磁及转子过电压保护装置技术条件 第4部分：灭磁容量计算 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 1~3 business days |
| Issued on: | 2019-06-04 |
| Implemented on: | 2019-10-01 |
| Professional Classification: | DL-Electricity |
| Related Topics: | Capacity Calculation
magnetic field energy electromagnetic device parts off % magnetic field quenching Capacitive voltage-dividing power device technology dl/t2011-2019 dl/t1966-2019 dl/t5784-2019 dl/t5787-2019 dl/t 5786-2019 dl/t 799 -2019 dl/t 5796-2019 |
Introduction
Interpretation of the core content of the standard
This standard systematically specifies the calculation method of the demagnetization capacity of synchronous generators for the first time, focusing on solving the matching design problem of field circuit breaker and non-linear resistor. The technical points include:
- Establish a fifth-order Parker equation model considering dual damping windings
- Clearly define three typical working conditions such as no-load/load mis-excitation
- Propose an engineering algorithm for nonlinear resistance parameters α and c
Comparison of key technologies
| Dimension | Traditional method | Standard method |
|---|---|---|
| Model accuracy | Third-order simplified model | Fifth-order full-parameter model (including d/q-axis damping windings) |
| Saturation processing | Linear approximation | a+bEqnnonlinear fitting |
| Operating condition coverage | Single no-load operating condition | Mis-excitation + three-phase short circuit composite operating condition |
Demagnetization capacity calculation implementation points
Parameter acquisition process
- Obtain the 23 generator parameters listed in Table 1 from the OEM
- Determine the saturation coefficient a/b/n by fitting the no-load characteristic curve
- Calculate the nonlinear coefficient α according to the demagnetization resistance configuration
Simulation calculation steps
1. Construct the fifth-order model of equations (1)-(4) 2. Set the operating conditions in Section 4.3 3. Solve the energy integral equation of formula (9) 4. Take the maximum value × 1.25 safety factor
Engineering application case
A 700MW hydro-turbine generator uses zinc oxide nonlinear resistor for demagnetization:
- Initial parameters: Ifdmax=3×2895A, ude_max=3500V
- Calculated: α=0.15, c=3500/(28953)≈0.042
- Under the short-circuit condition at the machine end, EZR=18.7MJ, and the actual selected resistor is 25MJ
Standard evolution analysis
Compared with DL/T 583-2007, this standard has the following major breakthroughs:
- New Appendix A provides a standardized processing method for saturation characteristics
- Clarifies the differences in excitation delays for different types of machines (salient pole/hidden pole)
- Introduces the engineering estimation formula (10) to solve the early design problems
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