DEIF AGC-2 Controller: The Ultimate Guide to Automatic Control and Protection of Generator Sets



DEIF AGC-2 Controller: The Ultimate Guide to Automatic Control and Protection of Generator Sets

In the modern power supply system, diesel generator sets serve as backup power sources, islanded power sources, or core equipment for grid connected operation. The reliability, flexibility, and intelligence level of their control systems directly determine the quality of power supply and operational safety. Traditional control schemes based on discrete components or simple logic are no longer sufficient to meet increasingly complex application scenarios, such as automatic mains fault switching, multi machine parallel connection, peak shaving, and hybrid operation with renewable energy.

In this context, the AGC-2 Multi line 2 automatic generator set controller launched by DEIF, as a comprehensive control unit based on microprocessors, highly integrates the protection, control, measurement, and communication functions of the generator. It is not only the brain of the generator set, but also the digital bridge connecting the unit with the upper monitoring system. This article will deeply analyze the hardware architecture, core functions, operating modes, and engineering debugging points of AGC-2, providing engineers with comprehensive technical references from theory to practice.

System Overview and Hardware Architecture: Building a Robust Hardware Platform

Understanding the hardware design philosophy of AGC-2 is the primary step towards successful application and troubleshooting. This controller is designed specifically for applications ranging from small to large generator sets, with its notable features being modularity and scalability.

1. Core processing and measurement unit

AGC-2 is equipped with a complete three-phase voltage and current measurement circuit, which can collect real-time electrical parameters of the generator, busbar, and mains power. All measurement values and alarm information can be clearly displayed on the LCD screen, which supports remote installation and provides convenience for human-computer interaction. The controller uses high-performance microprocessors internally to ensure real-time computation of complex protection algorithms (such as ANSI standard protection) and PID control laws.

2. Flexible I/O interface configuration

The strength of AGC-2 lies in its highly flexible input-output interface, which allows it to adapt to various engine and switchgear configurations.

Engine interface card: The standard configuration provides multiple engine interface cards (such as M1, M2), supporting different types of sensors and actuators. For example, the M1 interface card provides 2 configurable digital inputs and 3 digital outputs, while the M2 tab expands with more digital inputs and VDO analog inputs for direct connection to sensors such as oil pressure, water temperature, fuel level, etc., without the need for additional transmitters.

Analog input: The controller supports multiple types of analog input. In addition to receiving standard 4-20mA signals for measuring oil pressure, liquid level, or power signals from external transmitters, it also supports PT100 and VDO sensors, providing direct interfaces for non electrical quantity monitoring such as temperature and pressure.

Digital quantity and relay output: AGC-2 is equipped with freely configurable digital inputs and relay outputs. These I/O points can be flexibly programmed through the onboard M-logic logic configuration tool, enabling simple alarm indication to complex logic interlocking control, such as "start preparation" relay, circuit breaker opening and closing control, "idle running" control, etc.

Deep analysis of operating modes: from standard applications to advanced strategies

The strength of AGC-2 lies not only in its hardware, but also in the various specialized operating modes preset in its firmware, which can cover almost all application scenarios from single machine to multi machine, from islanding to grid connection.

1. Automatic Mains Fault Switching (AMF)

This is one of the core application modes of AGC-2. When the mains power is normal, the load is powered by the mains power and the generator is in standby mode.

Fault detection and startup: When the controller detects that the mains voltage or frequency exceeds the set threshold (set through menu 6590 Mains failure voltage and 6600 Mains failure frequency) and after a delay confirmation (tFD, i.e. Mains failure delay), the generator set will be automatically started.

Switching logic: AGC-2 supports two switching logics: one is "disconnect first and then close", which means that the mains circuit breaker is disconnected while starting the generator, and then the generator circuit breaker is closed when the generator voltage/frequency meets the standard; The second is "generator priority", which means starting the generator first and waiting for its voltage/frequency to meet the standard, then disconnecting the mains circuit breaker and closing the generator circuit breaker. Users can select through the 6595 Mains fail. control parameter.

Mains recovery and return: When the mains is restored and confirmed by the Mains OK delay, the controller will perform a reverse switch. If the "Back synchronization" function is enabled, the generator circuit breaker will synchronize with the mains power to achieve seamless load transfer and avoid impact on the load; Otherwise, the conversion of "break first, then close" will be executed.

2. Load management: fixed power, peak shaving, and load transfer

AGC-2 is not only an emergency power controller, but also an active energy management system.

Fixed power/Base load operation: In this mode, the generator operates in parallel with the mains and always outputs a constant power (set through the 6550 Fixed power setpoint menu). This is often used to reduce the basic load of purchasing electricity from the grid using self owned power plants, or to provide stable base load support for unstable energy sources such as photovoltaics and wind power.

Peak shaving: This mode aims to limit the maximum power that users can obtain from the grid in order to reduce demand electricity bills. Monitor the total power of the imported mains through an external 4-20mA power sensor. When the mains power exceeds the set "maximum mains import power", AGC-2 automatically starts the generator and increases its output to "cut off" the excess peak load. When the mains load drops, the generator is unloaded and shut down.

Load take over: This mode is commonly used for testing or scheduled maintenance. It can smoothly transfer the load from the mains level to the generator, or vice versa. The transfer process can be a synchronous "first connect and then disconnect" to ensure uninterrupted power supply to the load; It can also be a "break and then close" without synchronization, during which the load will be briefly interrupted.

3. Multi machine parallel connection and power management (options G3/G5)

For situations that require high reliability and high power output, AGC-2 supports parallel operation of multiple generator sets.

Option G3 (Load Distribution): Supports automatic sharing of active and reactive power between multiple units through load distribution lines (usually analog or CAN bus).

Option G5 (Power Management): On the basis of load distribution, the "Power Management" function has been added. The system will automatically determine the number of generator sets to be put into or out of operation based on the total load size, and manage the opening and closing of the bus tie circuit breaker to achieve optimal economic operation and redundancy management of the generator sets. This is an ideal solution for building backup power systems for large power plants or critical locations.

Synchronization control technology: the key to achieving seamless grid connection

For situations where parallel connection with the mains or other generators is required, precise synchronization is a prerequisite for ensuring safety and avoiding equipment damage. AGC-2 provides two flexible synchronization methods.

1. Dynamic synchronization

This is the default synchronization method for AGC-2. The principle is to operate the standby generator at a frequency slightly higher than the grid (or bus) (i.e. positive slip frequency). The controller sends a closing command in advance by calculating the slip frequency and the closing time of the circuit breaker, so that the circuit breaker closes at the moment when the voltage vectors coincide (with zero phase difference). The advantage of doing so is that the synchronization speed is fast, and after closing, the waiting unit will naturally bear a part of the load (small positive slip corresponds to the output of active power), effectively preventing reverse power tripping. The relevant settings can be completed in the 2020 Dynamic Synchronization menu.

2. Static synchronization

In this mode, the frequency of the generator to be connected will be precisely adjusted to be almost identical to the grid frequency (with a deviation usually within 50mHz). Subsequently, a phase controller begins to operate, gradually reducing the phase angle difference between the two by adjusting the generator frequency until the closing is completed within the preset "closing window". This method can achieve "zero impact" grid connection, and there will be no significant load fluctuations after closing. It is particularly suitable for connecting load sensitive to impact or connecting no-load transformers (to prevent excitation inrush current). The setting for static synchronization can be found in the menu 2030 Static synchronization.

Fault safety and status monitoring: building multiple protection systems

As the last line of defense for the generator set, the reliability of the protection function is crucial. AGC-2 integrates comprehensive ANSI protection functions and provides systematic fault handling logic.

1. Comprehensive protection function

Electrical protection: including reverse power protection (ANSI 32) (menu 1010), overcurrent protection (ANSI 51) (menu 1020/1030), as well as overvoltage, undervoltage, overclocking, underfrequency and other protections implemented through extended tabs.

Engine protection: Monitor oil pressure, coolant temperature, and fuel level through analog input. In the parameter menu, independent action values (Setpoint), action delays (Timer), enable conditions (Enable: OFF/ON/RUN), and fail classes can be set for each alarm.

2. Fail class logic

The brilliance of AGC-2 lies in its Fail class system. Users can assign different processing methods of 1-6 levels for each alarm:

Alarm: Only display and output alarm signals.

Warning: Remind the operator to pay attention.

Trip of GB: Immediately trip the generator circuit breaker.

Trip and stop: First unload (if there is power management function), then trip GB and stop.

Emergency Shutdown: Without uninstallation, immediately disconnect the GB and perform an emergency shutdown.

Trip of MB: Open the mains circuit breaker.

This refined level division enables engineers to preset the optimal response strategy based on the severity of the alarm, maximizing the safety of personnel and equipment. For example, "overspeed 2" can be configured as an emergency stop (Fail class 5), while "low fuel level" can only be configured as an alarm (Fail class 1).

Practical Application of Parameter Configuration and Engineering Debugging

AGC-2 provides two parallel parameter access paths: local settings through the controller's built-in LCD screen and buttons, or more efficient and intuitive configuration using PC tool software M-Vision. Parameters are grouped by function, such as Protection, Control, I/O, System, etc. Each parameter has a unique menu number.

1. Typical configuration process

Set basic parameters: In the System>General setup menu, set basic parameters such as rated frequency (6011), rated power (6012), CT/PT ratio (6030/6040), etc.

Configure operating mode: Select the application mode in 6060 Gen set modes, such as AMF or Island operation.

Set protection parameters: Enter the Protection menu and configure protection settings such as reverse power and overcurrent, as well as their corresponding fail classes.

Configure input/output: In the Input/output menu, assign functions to digital inputs (such as "remote start", "emergency stop"), and assign action objects to relay outputs (such as "start relay", "alarm horn"). In Binary input setup, the type of each digital input can be set to normally open (NO) or normally closed (NC), which is crucial for matching external dry contact signals.

Synchronization parameter tuning: In the Control>Synchronization menu, select the synchronization type (2010) and set key parameters such as maximum slip frequency (2021) and maximum voltage difference (2023).

2. Key points for troubleshooting common faults

Unit cannot start: First check if the Start prepare, Start ON time, and Start OFF time settings in the Start menu match the engine starter characteristics. Secondly, confirm that the Running feedback type (frequency, speed, digital input) is selected correctly. If using the speed signal, the number of teeth on the flywheel should be set correctly in the 6160 Remove starter.

Synchronization failure or significant impact on closing: Check if the df max/min (maximum/minimum slip frequency) setting in Dynamic synchronization is reasonable. Setting it too small may result in excessive synchronization time; Checking whether the breaker delay is consistent with the actual breaker action time is the key to achieving precise closing.

Reverse power alarm misoperation: Check the Setpoint and Timer settings of the reverse power protection to ensure that their settings are lower than the normal operating power of the generator under no-load or light load, and cooperate with appropriate delay to avoid power fluctuations at the moment of grid connection. At the same time, it is confirmed that positive slip is used in the synchronization logic to keep the unit in the "output" state after grid connection.