Switch power source for digital relay protection
Technical field
The present invention be directed to the digital relay protection device to some special technique index requests of power supply and a kind of Switching Power Supply that designs belongs to the relay protection of power system technical field.
Background technology
Along with the large-scale application of digital relay protection device in electric substation automation system, the reliability of protective relaying device becomes a very important problem.The power supply that belongs to a protective device part, the height of its performance directly affects the protective relaying device whole reliability.Switch power source for digital relay protection is a multiple-output electric power; be input as AC/DC universal, output has three groups of voltages, and+5V provides the working power of digital circuits such as CPU; ± 15V supplies with data acquisition system as analog power, and+24V is used for switching value input and output loop.Compare with conventional power supply; the used for relay protection power supply has increased some special technique indexs; as export that overvoltage/undervoltage protection, 5V cooperate with the sequential of 24V and more high-grade electromagnetic compatibility requirement etc.; its objective is that in order to improve the security reliability of power supply the problem owing to power supply of preventing causes the misoperation of protective relaying device.
Conventional power supply all requires overvoltage protection to output, and what mainly consider is that the too high meeting of output voltage damages back grade load circuit, and under-voltage owing to influence the less design protection of just refusing.The used for relay protection power supply is because its special application background and the size of output voltage is had stricter control.
The power initiation time is the time of power supply when being energized to output voltage and rising in the voltage stabilized range, and the retention time is the time of power cut-off outside output voltage drops to voltage stabilized range the time.Conventional multiple-output electric power is to the startup and the not requirement successively of retention time of each road output.Used for relay protection power requirement starting up 5V settling time is prior to 24V40~140ms, and shutdown retention time 5V is later than more than the 24V 20ms.5V voltage is set up earlier during startup, and CPU finishes initialize routine in the protective device, enters normal operating conditions, leaves the loop signal level state and determines, can not cause the protective device malfunction.24V disappears prior to 5V and also is based on this purpose during shutdown.
Used power supply generally has only 5V output to be furnished with short-circuit protection, output over-voltage protection on the present digital relay protection device; there is power supply start 5V to set up sequential prior to 24V; and non-transformer shutdown 5V is later than 24V disappearance sequential; the reliability that these have all reduced power supply has increased the power factor ratio in the protective relaying device misoperation.
Summary of the invention
Technical problem: in order to realize the special technique index request of digital relay protection device to power supply; the present invention has designed a switch power source for digital relay protection, has realized that overvoltage/undervoltage protection, short-circuit protection and the 5V of each road output and the switching on and shutting down sequential of 24V cooperate.
Technical scheme: switch power source for digital relay protection of the present invention, by input circuit, electric power main circuit, power supply output abnormality protection module, the start time schedule controller, the shutdown time schedule controller is formed, the output of input circuit and shutdown time schedule controller, electric power main circuit connects, 24V power on-off control circuit in the output termination electric power main circuit (2) of shutdown time schedule controller, 5V in the electric power main circuit, 15V, 24V three road out-put supply correspondences are connected to the 5V supply monitor in the power supply output abnormality protection module, the 15V supply monitor, the input of 24V supply monitor, the 5V supply monitor, the 15V supply monitor, the output of 24V supply monitor connects the input of abnormity of power supply controller respectively, the PWM controller in the output termination electric power main circuit of abnormity of power supply controller; The input termination 5V out-put supply of start time schedule controller, the 24V power on-off control circuit in the output termination electric power main circuit.
24V power on-off control circuit in the electric power main circuit is made of the power switch pipe of gate source voltage may command folding, the start time schedule controller is a charging delay control circuit, and its output inserts the first grid source control optical coupler " U1 " of power switch pipe " Q1 " in the 24V power on-off control circuit; The shutdown time schedule controller is an electric power main circuit ac input end dead electricity quick sampling circuit, and two output " off_A, off_K " inserts the second grid source control optical coupler " U2 " of power switch pipe " Q1 " in the 24V power on-off control circuit.
Adopt the single-ended reverse exciting topological structure to form the main circuit of power supply, power switch pipe is driven by current mode controller UC2842, and 5V master's output is furnished with the accurate optocoupler feedback circuit of band TL431.The input power supply inserts the primary winding through behind EMI filtering, full-bridge rectification and the big capacitor filtering, import and establish under-voltage protection, transformer three components from secondary winding export respectively 5V, ± 15V and 24V voltage.
5V, 15V, three groups of outputs of 24V all are furnished with voltage monitoring circuit, and the output of each road monitoring voltage is in series, and jointly controls the compensation pins of UC2842.When overvoltage/undervoltage was exported on arbitrary road, series loop was cut off, and UC2842 is turn-offed in control, and power supply enters " having the hiccups " guard mode and disappears until abnormal conditions.When the output of arbitrary road is short-circuited, the transcient short circuit time current surge, the voltage sharp fall causes the output under-voltage protection, short-circuit protection has been brought into the category of output voltage protection.
Be furnished with an IRFZ44N switching tube in the 24V output loop, 5V output realizes power supply starting up sequential by this switching tube of delay circuit control conducting.Regulate the delay circuit parameter and can conveniently realize the length of delaying time.During the power supply shutdown, the dead electricity sample circuit detects power cut-off, and the control on-off switching tube cuts off 24V output, and 5V output is continued to keep a period of time by the energy of storing on the big electric capacity of input filtering, reaches the requirement of shutdown sequential.
Beneficial effect: the present invention obtains following beneficial effect:
(1) design has realized overvoltage/undervoltage protection, the short-circuit protection of each road output of switch power source for digital relay protection, and short-circuit protection and overvoltage/undervoltage protection are blended together, and circuit is simply effective.
(2) design has realized that power supply output 5V cooperates with the switching on and shutting down sequential of 24V, satisfies different band and carries sequential requirement under the situation.
Description of drawings
Fig. 1 is the power supply architecture schematic diagram.
Fig. 2 is the circuit theory diagrams of input circuit 1.
Fig. 3 a is the left side of the circuit theory diagrams of electric power main circuit 2, and Fig. 3 b is the right-hand part of the circuit theory diagrams of electric power main circuit 2.
Fig. 4 is the circuit theory diagrams of power supply output abnormality protection module 3.
Fig. 5 is the circuit theory diagrams of start time schedule controller 4.
Fig. 6 is the circuit theory diagrams of shutdown time schedule controller 5.
Have among the above figure: input circuit 1, Electromagnetic interference filter 11; Electric power main circuit 2, input under-voltage protection device 21, feedback circuit 22, PWM controller 23,24V power on-off control circuit 24; Power supply output abnormality protection module 3, 5V supply monitor 31,15V supply monitor 32,24V supply monitor 33, abnormity of power supply controller 34; Start time schedule controller 4, shutdown time schedule controller 5.
Embodiment
Among Fig. 1, switch power source for digital relay protection, by input circuit 1, electric power main circuit 2, power supply output abnormality protection module 3, start time schedule controller 4, shutdown time schedule controller 5 is formed, the output of input circuit 1 and shutdown time schedule controller 5, electric power main circuit 2 connects, 24V power on-off control circuit 24 in the output termination electric power main circuit 2 of shutdown time schedule controller 5,5V in the electric power main circuit 2,15V, 24V three road out-put supply correspondences are connected to the 5V supply monitor 31 in the power supply output abnormality protection module 3,15V supply monitor 32, the input of 24V supply monitor 33, 5V supply monitor 31,15V supply monitor 32, the output of 24V supply monitor 33 connects the input of abnormity of power supply controller 34 respectively, the PWM controller 23 in the output termination electric power main circuit 2 of abnormity of power supply controller 34; The input termination 5V out-put supply of start time schedule controller 4, the 24V power on-off control circuit 24 in the output termination electric power main circuit 2.
24V power on-off control circuit 24 in the electric power main circuit 2 is made of the power switch pipe of gate source voltage may command folding, start time schedule controller 4 is charging delay control circuits, and its output inserts the first grid source control optical coupler of power switch pipe in the 24V power on-off control circuit 24; Shutdown time schedule controller 5 is electric power main circuit 2 ac input end dead electricity quick sampling circuit, and two output inserts the second grid source control optical coupler of power switch pipe in the 24V power on-off control circuit 24.
When output overvoltage/undervoltage or short circuit appearred in power supply, power supply output abnormality protection module 3 control power cutoff main circuits 2 were realized the protection to power supply.The 5V out-put supply of electric power main circuit 2 inserts start time schedule controller 4, and the output of start time schedule controller 4 inserts electric power main circuit 2, the 24V out-put supply of control electric power main circuit 2.The output of input circuit 1 inserts shutdown time schedule controller 5, and the output of shutdown time schedule controller 5 inserts electric power main circuit 2, the 24V out-put supply of control electric power main circuit 2.
1) input circuit
Among Fig. 2, power supply input inserts Electromagnetic interference filter 11, filtering common mode disturbances and differential mode interference through one and the Transient Voltage Suppressor RV1 that connects.An output serial connection fuse F1 of Electromagnetic interference filter 11, another output serial connection piezo-resistance RT1, the other end of fuse F1 and piezo-resistance RT1 inserts mains switch S1.
2) electric power main circuit
Among Fig. 3, the output of input circuit 1 is through over commutation, filtering, insert the primary winding, PWM controller 23 provides power supply by the direct current behind the rectifying and wave-filtering, realize self-starting, the conducting of power controlling switching tube and shutoff, transformer secondary output winding and feedback winding output voltage, the power supply of PWM controller 23 changes by the feedback winding at this moment provides.Through secondary output 5V after the single-ended reverse exciting DC-DC conversion, ± three groups of direct voltages of 15V, 24V.Input under-voltage protection device 21 monitors the filtered dc voltage value of input; if be lower than the under-voltage protection value; triode Q6 saturation conduction in the input under-voltage protection device 21, the compensation pins voltage of pwm control circuit UC2842 is pulled low to below the 1V in the PWM controller 23, and PWM controller 23 turn-offs.The 5V out-put supply inserts feedback circuit 22, feedback circuit 22 be band voltage-stabiliser tube TL431 precise light coupler feedback circuit, to guarantee the lasting accuracy of 5V.± 15V and 24V are furnished with the voltage self-regulation circuit of band voltage-stabiliser tube TL431, with the control output voltage deviation.The 24V out-put supply inserts 24V power on-off control circuit 24, and 24V power on-off control circuit 24 is made of the power switch pipe of gate source voltage may command folding.The output of start time schedule controller 4 inserts a grid source control optical coupler of power switch pipe in the 24V power on-off control circuit 24, two outputs of shutdown time schedule controller 5 insert another grid source control optical coupler of power switch pipe in the 24V power on-off control circuit 24, realize the control to the 24V out-put supply.
3) power supply output abnormality protection module
Among Fig. 4, the output of 5V supply monitor 31,15V supply monitor 32 and 24V supply monitor 33 inserts abnormity of power supply controller 34, and the output of abnormity of power supply controller 34 inserts PWM controller 23.In the 5V supply monitor 31, when output voltage was in normal allowed band, voltage-stabiliser tube TL431 diode D5 turn-offed, diode D6 conducting, optical coupler U4 conducting.During output overvoltage, voltage-stabiliser tube TL431 diode D5 conducting, diode D6 turn-offs, and optical coupler U4 turn-offs, and the overvoltage threshold value is set by resistance R 67, resistance R 47.Export when under-voltage, voltage-stabiliser tube TL431 diode D5, diode D6 and optical coupler U4 turn-off, and under-voltage threshold value is set by resistance R 68, resistance R 49.The principle of 15V supply monitor 32,24V supply monitor 33 is identical with 5V supply monitor 31.The corresponding states of the present optical coupler of output effective aspect of voltage monitor represents during the optical coupler conducting that voltage is in the normal allowed band, represents electric voltage exception when optocoupler turn-offs.Three road output voltages all are in just often, all conductings of three output optocouplers, and triode Q12 base voltage is lower than the conducting threshold value in the abnormity of power supply controller 34, and triode ends, the pwm control circuit UC2842 operate as normal in the PWM controller 23.When arbitrary road in three road output voltages takes place when unusual; triode Q12 obtains base voltage by the reference output pin of pwm control circuit UC2842; the triode saturation conduction; the compensation pins voltage of pwm control circuit UC2842 is pulled low to below the 1V; pwm control circuit 23 turn-offs, and power supply enters " having the hiccups " guard mode and disappears until abnormal conditions.Resistance R 70 and the capacitor C 49 of short duration charging time-delay that realizes powering in the abnormity of power supply controller 34, charging needs greater than the power initiation time time of delay.
During output short-circuit, output current rises sharply, and voltage collapse causes the output under-voltage protection, realizes short-circuit protection function indirectly.
4) start time schedule controller
Among Fig. 5, the negative electrode pin one of TL431 U7 links to each other with the end of resistance R 53, R54, links to each other with reference to the end of pin 3 with resistance R 80 capacitor C 51, and the anode pin two connects 5V ground.The other end of resistance R 80, R53 is linked+5V output, another termination 5V ground of capacitor C 51.The other end of resistance R 54 is connected to the light-emitting diode negative terminal of optocoupler U1 in the 24V power on-off control circuit 24.
5V output is by 51 chargings of 80 pairs of capacitor C of resistance R among Fig. 5, when the voltage of capacitor C 51 reaches 2.5V, voltage-stabiliser tube TL431 U7 conducting, optical coupler U1 conducting in the control 24V power on-off control circuit 24, switching tube Q1 in the 24V power on-off control circuit 24 obtains grid voltage, the Q1 conducting provides 24V output.The charge constant decision that the delay time of the relative 5V output of 24V is formed by resistance R 80 and capacitor C 51, but both parameter flexible delay time sizes adjusted.
5) shutdown time schedule controller
Among Fig. 6, diode D10, D11, D12, D28 form rectifier bridge, and an one input is connected to the input pin 1 of rectifier bridge BR1 in the electric power main circuit 2 by resistance R 78, and another input is connected to the input pin 3 of rectifier bridge BR1 in the electric power main circuit 2.The output of rectifier bridge also connects capacitor C 50, an one output is connected to the light-emitting diode anode of optical coupler U2 in the 24V power on-off control circuit 24 by resistance R 79, and another output is connected to the light-emitting diode negative terminal of optical coupler U2 in the 24V power on-off control circuit 24.
Rectifying and wave-filtering has been finished the sampling to power supply Alternating Current Power Supply information among Fig. 6, and resistance R 78, resistance R 79 are used to control the output voltage sizes values of this sample circuit.During normal power supply, this circuit keeps output, optical coupler U2 conducting in the control 24V power on-off control circuit 24.During dead electricity, capacitor C 50 rapid discharge offs, optical coupler U2 turn-offs in the control 24V power on-off control circuit 24, and switching tube Q1 loses grid voltage in the 24V power on-off control circuit 24, and switching tube Q1 turn-offs, and cuts off 24V output.Resistance R 78, resistance R 79, the parameter of capacitor C 50 are wanted suitable choosing, and sample circuit keeps certain voltage output when satisfying normal power supply, and the output of sample circuit voltage disappears fast during dead electricity.