Skip to main content

Digital Overcurrent Relay

Digital Overcurrent Relay

The overcurrent relay is the most commonly used for a type of protection relay protection of distribution systems. Digital relays are extensively used in the power industry operation. They operate when the circuit current exceeds the predetermined value. The microprocessor uses a multiplexer for sensing the fault currents in a number of circuits and sub-circuits. The microprocessor accepts signals in the voltage farms, the CT fault current derived is first converted into proportionate voltage signals, 'and then fed to the rectifier, multiplexer, analog to digital converter, and the microprocessor.

Block diagram of Digital Overcurrent Relay

The output of the rectified voltage signals is fed into the multiplexer. The microprocessor (microcomputer) then sends a command for switching ON the desired channel of the multiplexer in order to obtain the rectified voltage in the particular circuit.

Digital Overcurrent Relay

Since the microprocessor needs digital signals, the output of the multiplexer is fed into the analog to digital converter (A/D). Again, the microprocessor sends a signal to the A/D for starting the conversion and reads the end of the conversion signal to examine whether the conversion is over and compares the signal with the pre-determined pick-up value.

Benefits of Digital Overcurrent Relay 

  1. Lower cost and the ability to provide a full range of characteristics in one product.
  2. The required characteristics can be selected using the relay front panel
  3. Only one current input is required per relay.

Popular posts from this blog

RS Aggarwal Aptitude Book PDF Free Download

RS Aggarwal Aptitude Book PDF Free Download RS Agarwal Aptitude Book PDF Free Download: Quantitative Aptitude by R.S Aggarwal is a standout amongst the most inclining books among the hopefuls getting ready for Bank PO, PO, MBA, RBI, IBPS, CAT, SSC, IAS, PSC, Hotel Management, Railway Recruitment Exams, and other aggressive and placement tests. This book is suggested by different specialists in this field. This book covers relatively every theme which is being requested for the focused exams. On the off chance that you are looking to Download RS Aggarwal Quantitative Aptitude PDF's most recent version with the expectation of complimentary then you appear to be at the correct place.    Download PDF  RS Aggarwal Reasoning  In English RS Agarwal Aptitude Book PDF Free Download This book covers Problems on Surds and Indices, Simplification, Numbers and Ages, Pipes and Cisterns, Boats and Streams, Problems on Trains, Simple and Compound Interests, Time and Work, Permutations and Combina

Limitations of Terzaghi Theory

Limitations of Terzaghi Theory The value of the coefficient of consolidation has been assumed to be constant.  The distance d of the drainage path cannot be measured accurately in the field. The thickness of the deposit is generally variable, and an average value has to be estimated.  There is sometimes difficulty 1n locating the drainage face, and sometimes thin previous seams that can act as good drainage faces are missed in the boring operations. The equation is based on the assumption that the consolidation is one-dimensional. In the field, the consolidation is generally 3-dimensional. The lateral drainage may have a significant effect on the time rate of consolidation. The initial consolidation and secondary consolidation have been neglected. Sometimes these form an important part of the total consolidation. In actual practice, the pressure distribution may be far from linear or uniform.

Comparison between VSI and CSI

Comparison between VSI and CSI In power electronic systems, inverters are an essential component that converts direct current (DC) into alternating current (AC). There are two main types of inverters used in power electronic systems: Voltage Source Inverters (VSI) and Current Source Inverters (CSI). Both have their own unique advantages and disadvantages, and the choice of which to use depends on the specific application and the desired outcome. Comparisons between voltage source inverters and current source inverters are as follows. In voltage source inverters, the input voltage is maintained constant and the amplitude of the output voltage does not depend on the load. However, the waveform of load current, as well as its magnitude, depends upon the nature of load impedance.  In current source inverters (CSI), the input current is constant but adjustable. The amplitude of output current from CSI is freelance of the load. However, the magnitude of output voltage and its undulation outp