Diesel Generator Sets – Calculation of Transient Reactance and Terminal Voltage

This material presents a methodology for analyzing the electrical behavior of diesel generator sets during transient operating conditions. The document allows the calculation of the alternator transient reactance required by the system and the evaluation of terminal voltages during the application of constant loads, variable loads and motor starting conditions.

The study assists in the proper specification of diesel generator sets used in hydroelectric power plants, substations and industrial facilities, enabling verification of voltage limits, operational performance and compatibility between generators and connected loads.

• Electrical characteristics of alternators.
• Alternator transient reactance.
• Impedance and impedance angle.
• Constant-power loads.
• Variable-power loads.
• Currents during transient conditions.
• Electric motor starting.
• Influence of motor starting currents.
• Internal alternator voltage.
• Alternator terminal voltage.
• Operational voltage limits.
• Simultaneous application of different loads.
• Criteria for diesel generator set specification.
• Complete worked example.
• Technical PDF document.
• Excel calculation spreadsheets. 

Electrical engineers, designers, consultants, operators, maintenance personnel and professionals involved in diesel generator set specification and power system analysis. 

• Technical PDF Document.
• Excel Calculation Spreadsheets. 

Spreadsheet for automatic  calculating of transient reactance 

• Complete version: provides visibility of all intermediate calculation values.
• Simplified version: allows input data entry to generate final results.
• No password is required to unprotect the spreadsheets.

Spreadsheet for automatic  calculating of alternator terminals voltage 

• Complete version: provides visibility of all intermediate calculation values.
• Simplified version: allows input data entry to generate final results.
• No password is required to unprotect the spreadsheets.