In this note, we are going to learn a topic called “What is Microprocessor Based Relay?“, its block diagram and working principle as well. Welcome to Poly Notes Hub, a leading destination for Engineering Notes.
Author Name: Arun Paul.
What is Microprocessor Based Relay?
A Microprocessor-based Relay is a form of protective relay used in electrical systems to monitor and control the flow of current. Unlike traditional relay systems, which rely on electromechanical components, microprocessor-based relays use digital processing technologies.
These relays have a microprocessor unit (MPU) that evaluates incoming data from sensors and other input devices to determine the state of the electrical system. They can execute sophisticated functions including defect detection, localization, and isolation with better precision and speed than their analog counterparts.
Block Diagram of Microprocessor Based Relay
Below we shows the microprocessor based relay block diagram and describe its important sections –
- MUX or Multiplexer: The multiplexer selects and routes different input signals to the analog-to-digital converter (ADC). It enables the microprocessor to sample several input signals sequentially.
- Anti-Aliasing Filter: An anti-aliasing filter is applied to the signals prior to their sampling by the ADC. In order to avoid aliasing, which can skew the signal’s digital representation, this filter eliminates high-frequency components from the signals.
- Sample-and-Hold (S/H): Throughout the conversion process, the sample-and-hold circuit catches and maintains a steady level of the analog signal. This ensures that the signal remains stable as it is translated to digital form by the ADC.
- Analog-to-Digital Converter (ADC): The ADC converts analog input signals into digital data that can be processed by the microprocessor. It converts a continuous analog signal into discrete digital values.
- Microprocessor: The microprocessor is the relay system’s primary processing unit. It receives digital signals from the ADC, processes them using pre-programmed algorithms, and then makes decisions depending on the relay’s operating logic. The microprocessor also controls the relay’s output using internal computations and external orders.
- Output Control: The microprocessor transmits control signals to the output stage, which may include trip signals to open circuit breakers or other control actions to address power system problems or abnormalities.
Microprocessor Based Relay Working
The Microprocessor-based Relay works by receiving analog signals from the power supply and converting them into digital representation using an analog-to-digital converter (ADC). The microprocessor analyzes these digital data using specified algorithms to detect anomalies such as malfunctions. Based on its analysis, the microprocessor decides how to protect the system, sending commands to trip circuit breakers or activate other protective devices as needed.
In addition, the relay may communicate with external systems via interfaces such as serial or Ethernet ports to allow for remote monitoring and control. It also collects and retains data on detected defects for analysis and reporting purposes. Overall, the relay’s digital processing capabilities allow it to continuously monitor and protect the electrical system, assuring its safety and reliability.
Advantages of Microprocessor Based Relay
Below we listed some important merits of microprocessor-based relays –
- The digital processing capabilities of microprocessors allow for exact measurement and analysis of electrical characteristics.
- These relays can be programmed and adjusted to meet different system needs and operating situations.
- Microprocessor-based relays frequently include built-in event recording capabilities, allowing engineers to examine system performance under abnormal conditions.
Applications of Microprocessor Based Relay
Below we listed some important uses of microprocessor based relays –
- Microprocessor-based relays are widely employed to protect power systems from problems such as overcurrent, overvoltage, undervoltage, and frequency fluctuations. They can detect issues precisely and quickly, reducing downtime and protecting equipment.
- In industrial applications, microprocessor-based relays are used to safeguard motors against overloads, phase imbalances, and other electrical anomalies. They monitor motor performance and respond quickly to avoid motor damage or failure.
- Microprocessor-based relays can communicate over networks, allowing for remote monitoring and control of electrical systems. Operators can view real-time data, get alarms, and remotely alter relay settings to optimize system management.