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Arduino FreeRTOS Mutex Examples

In this section, we will explain using an example to demonstrate mutexes in Arduino using freeRTOSThere are two freeRTOS Mutex examples in this tutorial, the first example demands some hardware (LCD) While the second does not need any hardware, you can try out both if you have the resources.

In the last tutorial, we considered in detail: semaphores and mutexes and we also established the difference between binary semaphores and mutexes.
Just for a review:Recall that a mutex is a locking mechanism that implements the take and gives functionality in itself, unlike a binary semaphore. See this tutorial if you have not before continuing.
Example 1: Protecting the LCD Resource Using Mutex in freeRTOS
Program Description

In this program, we Demonstrated the use a 16x2 LCD display to implement a mutex.

The LiquidCrystal library works with all LCD displays that are compatible with the Hitachi HD44780 driver. you can usually tell them by their 16-pin interface.


* LCD RS pin to digital…

Synchronization and interconnection of Generating stations

Ever wondered how different generating stations are interconnected together for the production and transmission of electricity, and still perform in harmony as one single entity, before a generating station or  a generator can be connected together with another, some conditions must be met, in this article, we will be looking into these conditions and how it is carried out in a typical power industry.

Synchronization and Interconnection of Generators and Generating Stations.

The concept of synchronization is not only applied to grid connections, even in the bus transfers. To interconnect two or more ac power sources, the parties involved must have the same:

  • Frequency

  • Phase Sequence

  • Voltage

When all these parameters are the same, they can be connected together safely.

So how is this done in a power station?

Synchronization in a power industry can either take place manually or automatically. In the manual mode, the operator checks to ensure that the parameters are the same and then closes the circuit breaker or applies control to perform the necessary control action. This mode is no longer used in many power industries.

In the automatic mode, a synchronism check relay is used, in combination with Potential Transformers and Current Transformers in a PLC system which help monitor the two sets of parameters, if there is a voltage difference or frequency difference it will issue a control signal that will tend to correct the error.

For frequency difference, the speed of the turbine can be altered, for voltage difference, the excitation from the AVR will be altered to make sure they are the same before synchronization can take place.

Advantages of using a Centralized Grid System

So far, we have considered synchronization in a power station. Looking at many national grid systems, one may ask: Why should all generating systems connect to a central grid? What advantage do central grids pose to systems?

The following advantages are obtained in centralized grid systems.

  1. Allows the Participation of Old power stations: Less efficient and older plants can be used in an interconnected system, without an interconnected system, these plants are insufficient and inefficient to operate alone.

  2. Load Sharing: This is an important advantage of the interconnected system (excess) load on the grid can be shared by other stations interconnected with it.

  3. Short-Latency and Blackout requirements: Usually power is required to generate power (to start up the units and systems). In an interconnected system, a power station can easily get energized from the grid because other power stations are connected to it, however it cannot be able to do this if there were no such connections and thus might require more complex or costlier blackout system.

  4. Consistency in power Output: With the interconnection of systems, there is always power on the grid because it is rare for all the power stations to go dark at the same time, thus if one is out of the grid, another takes over the load and power transmission continues.


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