Automated Control System of Diesel Generator Sets

In today's society, the stability and continuity of power supply are crucial for all industries. Whether it is critical infrastructure such as hospitals, banks, telecommunications, and airports, or factories, enterprises, and hotels, any power interruption can cause significant losses and inconvenience. As a reliable backup power source, diesel generator sets, with the application of automated control systems, greatly enhance operational efficiency, reliability, and safety, ensuring continuous power supply and becoming an indispensable part of modern power systems.

Diesel generator set automated control systems can accurately and rapidly adjust the operational status of the generator. When the generator experiences abnormal conditions, the automated control system can quickly make judgments and take timely action, issuing corresponding alarm signals and emergency shutdown commands to prevent damage to the generator. At the same time, it can automatically start a backup generator, effectively shortening the power outage time and ensuring continuity of power supply. This is undoubtedly crucial for places with extremely high power supply requirements.

In addition, automated control systems can improve power quality indicators and operational economy, keeping all electrical equipment in good working condition. Electrical equipment generally requires high standards for frequency and voltage, with very narrow permissible deviation ranges. Automatic voltage regulators maintain constant voltage, while governors adjust frequency. Automated diesel power stations rely on automatic adjustment devices to regulate frequency and active power, accelerating the control and operation process, and improving system continuity and stability.

Once diesel power station automation is realized, it can timely change operational working conditions and adapt to system requirements. The generator operation process proceeds in a predetermined sequence without interruption and continuously monitors its completion. Taking emergency generator startup as an example, if manual operation is used, it would take 5–7 minutes at the fastest, whereas with automated control, it can usually start successfully in less than 10 seconds and restore power. This not only greatly reduces operation time but also lowers energy consumption and improves working conditions. The environment of the generator room can be quite harsh, which may affect operator health. Automated control systems create conditions for unattended operation, further enhancing generator operational safety and reliability.

Diesel generator set automated control systems are mainly composed of three parts: program control, analog control, and operational management control.

Program control is implemented according to a pre-designed operation sequence. Control signals only act discretely, and parameters are in the form of switch values. The form of control signals usually derives from the results of several logic operations. For example, generator start and stop operations belong to program control. Through this method, it ensures that the generator performs various operations accurately according to the predetermined program, avoiding risks caused by human operation errors.

Analog control regulates and adjusts by measuring the actual value of operational parameters of the equipment, comparing it with the set value, and adjusting the corresponding physical quantity according to the deviation. This type of control signal acts continuously, and the parameters are usually analog quantities, which can also be converted into discrete quantities over time through timed sampling. However, no matter how large the deviation, continuous adjustment should follow the set value. For example, the regulation of frequency and voltage belongs to analog control. Analog control ensures that generator operational parameters are always maintained at optimal conditions, improving power quality and operational efficiency.

Operational management control operates the diesel generator set according to the requirements of various operational conditions set by humans and the actual load demand, sequentially calling various automatic devices or corresponding programs to achieve safe control and economical operation. This control method comprehensively considers the generator's operational status and load demand, achieving efficient operation through reasonable scheduling and management, reducing operating costs, and improving economic benefits.

Diesel generator set automated control systems can be divided into the following four categories:

The first type of control method is relay and semiconductor device logic control. This method is simple and effective, but its shortcomings are also obvious. There are many components, complex circuits, and large size, resulting in relatively poor reliability. If additional functions are required, the control circuit must be modified, which increases maintenance and upgrade difficulty.

The second type of control method replaces semiconductor logic circuits with program controllers. This standardizes hardware and makes programming easier using dedicated languages. Control circuits can be modified via software conveniently. The adoption of large-scale integrated circuits reduces the number of components, and the software's self-check function improves reliability. This method partially solves the shortcomings of the first type, enhancing system stability and maintainability.

The third type of control method uses a microcomputer to replace manual operational management, forming a combination of program controllers, standardized analog controllers, and a microcomputer. Operations such as start, stop, paralleling, synchronization, and load distribution are treated as independent units connected to the microcomputer, implementing full-process automated control via software, making operation more convenient. However, backup measures are required to prevent loss of control in case the microcomputer fails. This method fully utilizes the microcomputer's powerful functions, achieving automated operational management and improving system intelligence.

The fourth type uses a microcomputer or PLC to achieve automated control of diesel generator sets. The hardware composition becomes simple, but reliable backup measures must be considered. This method fully leverages computer technology, transforming ordinary generator sets into automated ones. It can implement control, data processing, and scientific computation, with speed and accuracy fully meeting control requirements. Its outstanding advantage is storing three types of control programs in memory, with wiring limited to sensors and actuators, simplifying hardware and wiring, thus achieving high reliability and adaptability, and facilitating debugging and maintenance. This advanced control method provides strong technical support for automated generator operation and is widely used today.

One of the core functions of diesel generator set automated control systems is to ensure stable operation and safe handling through precise signal processing and comprehensive protection mechanisms. This section details how the system receives and processes various signals and how it rapidly takes protective measures in case of potential faults.

The start and stop signals of automated generator sets mainly include main power abnormalities (including power failure, phase loss, voltage exceeding permissible values) and other signals set by users for specific generator purposes. These signals are sent to the monitoring system in a logical combination. When the logic value is 1, the generator starts automatically and operates according to the control process; when the logic value is 0, the generator stops automatically after a delay. The inspection of abnormal power signals generally uses phase failure protectors, voltage comparators, etc. For some control modules with built-in power inspection devices, power signal checking can be performed internally in the operating system without external inspection equipment.

To safely supply power to the load, generator voltage, current, frequency, and ATS status need to be monitored. If these parameters exceed limits, corresponding protection measures must be taken to prevent generator failure, accidents, or reduced power quality. Besides operational modes (such as automatic or manual), the diesel generator's operational conditions to be checked include whether startup is successful, whether speed is normal, whether lubrication oil pressure is sufficient, and whether temperature is abnormal. For protection, if startup fails, overspeed exceeds 110%, oil pressure is too low, or temperature is too high, the generator will automatically stop and alarm, while the device locks. Without manual intervention (unlocking), even if a start signal is received later, the generator will not start automatically. These signals are typically monitored using dedicated probes, such as speed sensors, pressure sensors, and temperature probes. These monitoring and protection measures effectively ensure safe generator operation, preventing equipment damage and power interruptions caused by faults.

Diesel generator set automated control systems play a critical role in modern power systems. They enhance generator operational efficiency, reliability, and safety, effectively ensuring continuous and stable power supply to meet high demands across various facilities. With ongoing technological advancements, the functionality and performance of automated control systems continue to improve, providing stronger support for generator operation. Whether for emergency power or grid-connected operation, automated control systems fully utilize their advantages to safeguard power supply. In the future, diesel generator set automated control systems are expected to see broader application across more sectors, providing more reliable power support for societal development and daily life.