Solid State Relays & Its

Transcription

1 Solid State Relays & Its Applications Presented By Dr. Mostaa Abdel-Geliel

2 Course Objectives Know new techniques in relay industries. Understand the types o static relays and its components. Understand Digital relay undamentals apply the dierent types o digital relays

3 Course contents Type o relay system General overview o static relays. Static Relay elements and design Computer applications to protective relaying. Digital relay undamentals Mathematical Bacground o digital relay. Applications o Digital relay Advanced topics in relaying system

4 Course outcomes Based on NARS (National Accreditation reerence Standard) the course should cover some intended learning outcomes - Knowledge and Understanding 2- sills -Intellectual Sills 2- Practical Sills 3- General Sills

5 Knowledge and understanding Understand electromechanical relays verses static and digital relay. Know recent developments in the area o microprocessor relays and protection systems. Demonstrate the utilization and various applications o digital relays in integrated apparatus protection. Know how to integrate protection and control in substations. Distinguish between dierent mathematical tools used in digital relay

6 Intellectual sills Determine the relay unction and classiy the relay types Determine the relay components Select the suitable mathematical tools to build digital relay algorithm Demonstrate the hardware and sotware o digital relay Report the main dierences between digital and static relay Apply digital relay or dierent electric equipments

7 Practical (Proessional) Sills Design a complete static relay Select the hardware that is suitable or use in digital relays eectively. Design a digital relay or dierent electric equipment. Dierentiate between the suitable relay algorithm or a speciied relay unction Manipulate the measured signal numerically Perorming laboratory experiments to get amiliar with dierent types o protective relays

8 General sills Communicate eectively with colleagues and proessional engineers to interchange nowledge and inormation in the power engineering ield o practice. Prepare eective and inormative technical reports and present results on electrical power engineering. Using inormation technology (IT) to ollow the continuous advancement in electrical power innovations and technological applications. Practice digital relay operation and tuning

9 Lecture : Introduction Introduction to relaying system Multi-layer structure o power system Elements o protection system Type o protection devices Type o relaying system

10 Protective Relaying Power system is an essential and the main stem o modern industrial society, thereore increasing availability, saety and quality o power system is mandatory. The power system is always subject to almost un-measurable and unpredictable disturbances created by dierent abnormal reasons such as: random load changes Equipment and operator ailure Faults due to natural causes

11 Protective Relaying The unction o protective relaying is to promptly remove rom service any element rom the power system that stats to operate in an abnormal manner. The purpose is Limit urther damage o equipment Minimize danger to people Reduce stress on other equipments Maintain integrity and stability

12 Protective relaying is a device that detects abnormal power system conditions and initiates a corrective action as ast as possible in order to return the power system to its normal state. The response must be automatic, quic and cause minimum a mount o disruption o power system Main requirements o protective system Quic response Correct diagnosis o trouble Minimum disturbance to power system Absolute discrimination Sensitive and accurate Reliable Stable Thereore expensive and sophisticated equipment is needed to accomplish these tass.

13 Multi-layer structure o power system Three layered structure o power system Control Equipments Protective Equipment Apparatus such as (generator, Transormer, etc.) Power Apparatus Control Eq. which control voltage, requency, power, optimal economic and security in interconnected networ Relay: more ast than control and it acts to open and close Circuit Breaer (CB), which leads to changing structure o power system. While control acts continuously adjust system variations.

14 Elements o a Protection system Transducer Such as P.T and C.T. Breaer CB to isolate the ault Re lay To detect ault and remove it Supply Breaer Relay Supply Transducer To produce tripping power o breaer and operate relay Should be uninterrupted such as batteries and UPS

15 Relay Construction Based on the elements o protection system the relay construction can be divided into three subsystem Sensing Comparison Control action (trip)

16 Relay Function The relay unction is depending on the abnormal situation that should be protected so, the relay may be Over load Over and under voltage Over and under requency Reverse power Short circuit Etc. The selection o relaying unction depends mainly on the equipment that should be protected

17 Relay Types The relay types can be classiied based on the techniques used to perorm its unction such as Conventional (Electro-mechanical relay) Solid state relay Digital relay

18 Conventional relay It is an electro-mechanical device, it has the advantage that Robust Easy to maintenance While it has disadvantage Large size High power consumption It depends on moving parts which need more maintenance Each relay perorm a single unction

19 Example Discuss the basic structure o over current relay (OC)

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21 Lecture 2: Solid state relay Fundamentals Basic undamental o static relay Logic Signal conditioning Analog Signal Conditioning Comparator circuits Time delay circuit Example o static relay

22 Solid State Relay It has no moving parts most o its components are static device based on semi-conductor materials. The main parts Power system sensing protection Relay circuit Transducer and signal conversion Signal conditioning (Filtration) Circuit Breaer (CB) Trip Circuit Time delay unction Comparator unction Relay logic

23 Solid State Relay -Sensing: voltage and current sensors such as CT and PT 2- Protection: Ziner diode, current limiter, etc 3-Transducer: such as hall transducer, F/V, AC-DC, etc 4- Signal conditioning: Low pass ilter, 5- Comparer: voltage and current comparators, 6- Time delay circuit: trip time calculation circuit 7- Trip circuit: Signal conditioning to operate CB

24 Solid State Relay Advantages: Small size Easy to mounted Fast response Low power consumption No moving parts(less maintenance) Can perorm more sophisticated unction Disadvantages Less robust to vibration & Temp. Dierent circuit or dierent unction Less lexible

25 Signal Conditioning It is the Adjustment o signal to be suitable to the next stage (controller, display, etc ) or example Ampliication Attenuation Filtration Isolation Linearization Excitation Conversion Etc. Analog signal conditioning Binary signal Conditioning Digital Signal Conditioning

26 Logic Signal Conditioning Two state signal (high-low) High: 5v, 2V, 24v (dc) 24, 0, 220 v (ac) Buer (Isolation) Tri-state buer Input Output Using Transistor enable input enable output

27 Logic Signal Conditioning (cont.) Opt. isolation Relay 2. Inverter Photo Diode Photo transistor Photo triac V cc V CC input output output Input 3. Ampliier V CC Input output

28 Analog signal Conditionig It Depends mainly on OP-Amp

29 Analog signal Conditionig It Depends mainly on OP-Amp Unity Gain

30 Analog Signal Conditioning (Cont.) Addition and subtraction Integrator Linearization Comparator Normal comparator Hysteresis Output V l V h Input

31 Analog signal conditioning

32 Analog signal Conditionig Unity Gain Ampliier

33 Analog Signal Conditioning (Cont.) Addition and subtraction

34 Dierential amp

35 V out V in Analog signal conditioning Analog ilters V out V in c c

36 Analog signal conditioning Signal Integration V = o V i ( t ) dt R C G F t 0 Linearization?

37 Analog signal conditioning Signal Conversion Current to voltage Voltage to current Assignment Write a report about voltage-to-current and current-to-voltage methods

38 Comparator Circuit Amplitude (Direct or Integration) Phase (Direct or Integration) Hybrid (Direct or Integration)

39 Time delay Circuit The simple circuit to generate time delay is RC circuit It can be built using digital timer

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43 Example: over current relay

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47 Digital Relay Fundamentals Introduction Digital relay components Mathematical bacground How to implement discrete dierentiation and integration How to estimate a value between two sample or predict a value in the uture

48 Introduction Bacground Advantages o digital relay Overview o Digital relay structure

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52 Dierence equation. Bacward dierences. For continuous unction (t) 2. = (t o +h) 3. = n = n- - n- - Where t o is the initial value, h the sampling interval, the sampling number Forward dierences. = n = n- + - n-. Shit operator. + = (t +h) = E 2. +r = (t +rh) = E r 3. E=+

53 Forward interpolation Bacward interpolation

54 Estimation and data Prediction +r = (t +rh) = E r ;0<r< using bacward dierences ( r + ) r( r + )( r + 2) r( r + )( r ) ( r + n ) r 2 3 n + r = + r ! 3! n!! Using orward dierences ( r ) r( r )( r 2) r( r )( r 2)...( r n ) r 2 3 n + r = + r ! 3! n! By replacing the dierences operator by the equivalent orm the new equation is called equation

55 Example: ind the recursive equation o the bacward prediction unction by approximating the result to the second term ( ) ( ) ( ) ( ) ( ) ( ) ( ) ! 2! 2! = + + = + + = + + = r r r r c b a r r r r r r r r r ( ) ( ) ( ) 2!, 2! 2, 2! = = + + = r r c r r r b r r r a

56 Numerical dierentiation = lim + r = lim r 0 r r '' = lim r 0 r 2 2 r + 0 r = lim r 0 0 r 2 2 r ( t + rh ) ( t + rh ) Bacward 3... = + h 2 3 '' = '' 2 ( t ) = h ( t ) = orwrad '' = = '' ( t ) = h h ( t ) = ' ' ' ' '

57 Numerical dierentiation Approximate dierentiation First term ( ) ( ) ' ' = t Second term ( ) ( ) ' ' = h t h ( ) ( ) ( ) = + = 2 ' 2 ' ' 2 ' ' h h t h t

58 Numerical Integration Rectangle approximation 0 0

59 Sinusoidal-wave based algorithm Chapter 4: Pure sine wave algorithm Build a program to deduce the ollowing parameters - voltage magnitude 2-cureent magnitude 3- phase shit 4- circuit impedance (Z,R,x) For a given data ile (data) where sampling time ms and the signal requency 50hz each raw o the data ile is [sample#, v(),i()]