CN85205360U - Phase-sensitive rectification type pulsating current mode protective cut-out - Google Patents

Abstract

The utility model discloses a protector, which can prevent the electric shock casualty for person. The phase-sensitive rectification circuit which is composed of a polarity reversed amplifier is adopted to cause the electric shock action current to be completely irrelevant to the leakage current, and the action dead zone does not exist. The phase difference between the output signal of the zero sequence current transformer and the reference voltage can be eliminated, three sets of testing circuits with the same phase sensitive rectification, differentia, and positive negative pulse stuffing can respectively provide three phase fiducial signals, and the currents of the three phase electric shock action are the same. The structure of the zero sequence current transformer of the device and the protector is separated. The utility model has the advantages of convenient installation, simple structure, low cost, reasonableness, and efficient security protection.

Description

Phase-sensitive rectification type pulsating current mode protective cut-out

The utility model relates to low pressure and gets an electric shock and leakage protection equipment, is a kind of electric shock protection apparatus.Prevent the person electric shock injures and deaths in the rural low voltage network, be not easy to ignore.In the prior art; dissimilar protectors is arranged; " the multi-functional electrical shock protection relay of JIW-S " as the introduction of " the electric world " 10 phases of nineteen eighty-two; " current mode protective device with desirable operation characteristic " that " electronic science and technology " 1984 annuals are introduced or the like can both play security personnel's effect.But existing apparatus remain actual electric shock operating current be subjected to leakage current and phase effect big and exist operating dead zone or manufacturing cost height, complex process, zero sequence current mutual inductor output signal and baseline signal and power supply mutually differ compensation the time weak point such as adjustment difficulty.

The purpose of this utility model is, provide a kind of and make the electric shock operating current not be subjected to influence of leakage current fully and can eliminate harmful phase depending on rectification formula Pulse Electric flow pattern protector that differs between zero sequence current mutual inductor output signal, reference voltage and the power supply, to solve existing problem in the prior art.

The phase-sensitive rectifier circuit that the utility model adopts polarity inverting amplifier to constitute, make the electric shock operating current not be subjected to the influence of leakage current and eliminated the existence of operating dead zone, and with simple and easy method eliminate the zero sequence current mutual inductor output signal and and reference voltage between differ, and adopt phase depending on rectification, differential, positive negative pulse stuffing testing circuit.

The utility model is that the master constitutes by the four high guaily unit device of two cheapnesss, and its detailed principle is seen Fig. 9.Be provided with D in the machine ₁, D ₂Overload protection, in case damage 1A when short circuit current to earth takes place ₁, by W ₁Constitute the sensitivity regulator potentiometer that touches, leaks electricity, place the panel adjusted, display sensitivity; By W ₃, T ₁Constituting electric leakage adjusts; W ₄Be electric shock operating current adjust (be K value adjust); By 2A ₁, 2A ₂Constitute once automatic coincidence circuit, to make things convenient for electricity consumption; D ₁₇, D ₁₆For power supply and action indication luminous tube, place on the panel, with indication protector operating state; By AN ₂, AN ₁Form test and manual reset button, be used to check the operating state of protector and artificial the input to carry out.

Below in conjunction with accompanying drawing the utility model is made an explanation.

Fig. 1 is a pictorial diagram of the present utility model, it comprises zero sequence current mutual inductor (1), main frame (11) and main frame internal work circuit, the central part of instrument transformer (1) has the through wires hole (2) that allows the load circuit pass through, connecting (3) is communicated with instrument transformer (1) with main frame (11), main frame (11) has and is installed in touching residual operating current release handle (4) and being installed in the test button (6) of end face of end face central part, reset button (9), in button (6), action indication luminous tube (5) and power supply indication luminous tube (10) are arranged (9), and there is the terminal board (7) of terminals (8) and each terminals of expression the bottom of main frame (11).

Fig. 2 is a theory diagram of the present utility model.

Function about phase-sensitive rectifier circuit.(see that Fig. 3 (a) is by a transport and placing device unit 1A with the phase-sensitive rectifier circuit that polarity inverting amplifier constitutes ₂, transistor T ₁And R ₁, R ₂, R ₇Constitute.Work as T ₁Making switch uses and R ₁=R ₂=R ₇The time, the absolute value of the multiplication factor of this circuit is 1.U is for sinusoidal wave and establish itself and power supply homophase, T during positive and negative half cycle ₁And respectively conducting of D, as U〉〉 during the conducting voltage of PN junction, reference voltage U ' is a symmetrical square wave.If U _O1Differ φ with U ', the work wave shown in Fig. 1 (b) launches with Fuli's leaf-size class number, can get average DC component:

U _O2=-2E _m/ π .Cos φ=-0.9U _O1Cos φ (formula 1)

By the 2A among Fig. 2 ₃Constitute filtering and anti-phase direct current amplifier, with filtering U _O2In alternating current component, establishing its multiplication factor is U _O3/ U _O3=-K ₃For 1A ₁The current-voltage converter that constitutes is if establish it with I _oLinear transformation is U _O1, then conversion coefficient is K ₁=U _O1/ I _o, have: U _O3=-K ₃U _O2=-K ₃(0.9U _O1Cos φ)=0.9K ₁K ₃I _oCos φ

If K=0.9K ₁K ₃, then have:

U _O3=KI _oCos φ (formula 2)

(in the formula: I _oFor zero-sequence current, φ are zero-sequence current I _OWith the phase angle difference of reference voltage U ', K is a proportionality constant).

About eliminating the principle of leakage current to the influence of electric shock operating current.If I _LBe leakage current, I _HBe the stream that gets an electric shock, φ _LBe the phase angle difference of leakage current and u ', then in the low-voltage distribution system of normal operation,

_O=

_L+

_H, I _LBy the intrinsic physical structure of circuit is determined, only take place to change slowly with weather, generally between milliampere is to hundreds of milliamperes, φ _LAlso be between 0～360 °.As can be seen from Figure 2, power supply is provided mutually by C, thereby U is arranged _C' with C mutually differ φ _C, when respectively when the electric shock phenomenon takes place on mutually in C, A, B, I then _HWith U _C' differ and be respectively φ _C, 120 °+φ _C,-120 °+φ _C, this moment U _O3Variation be respectively as described below:

(1), electric shock phenomenon occurs in the C phase time and (sees Fig. 4 a): I _HC=0, U is then arranged _O3=KI _LCos φ _L, and when having the people to get an electric shock; U _O3C=KI ₀Cos φ _o=KI _LCos φ _L+ KI _HCCos φ _C,

△ U _O3C=U _O3C-U _O3=KI _HCCos φ _C(formula 3)

(2), electric shock occurs in A phase time (seeing Fig. 4 b): I _HA=0, then have

U _O3=KI _LCos φ _L, and when having the people to get an electric shock;

U _o3A＝KI _oCosφ _o＝KI _LCosφ _L＋KI _HACos(120°＋φ _C）

△ U _O3A=U _O3A-U _O3=KI _HACos(120 °+φ _C) (formula 4)

(3) electric shock occurs in B phase time (seeing Fig. 4 C): I _HB=0, U is then arranged _O3=KI _LCos φ _L, and when having the people to get an electric shock, have:

U _o3B＝KI _oCosφ _o＝KI _LCosφ _L＋KI _HBCos（－120°＋φ _C）

△ U _O3B=U _O3B-U _O3=KI _HBCos(-120+ φ _C) (formula 5)

△ U in formula (3), (4), (5) _O3Be equivalent to a transition voltage E through C ₃, R ₁₀Output voltage behind the integrating circuit, C ₃, R ₁₀Be the integration time constant in " filtering and DC amplify " circuit, △ U _O3Through C ₄, R ₁₄To produce △ U ' behind the differential circuit _O3, this equivalent circuit is shown as among the figure (5a) have:

${\mathrm{△\; U}}_{\mathrm{O\; 3}}\mathrm{=\; E\; ·\; (\; 1\; -\; e}{}^{\frac{T}{\tau }}\mathrm{)\; (\; 6\; )}$

τ=C in the formula ₃R ₁₀And,

${\mathrm{△\; U\; \prime }}_{\mathrm{O\; 3}}\mathrm{=\; E\; ·}\frac{n}{\mathrm{n\; -\; 1}}{\mathrm{(\; e}}^{-\frac{x}{n}}\mathrm{-\; e}{}^{\mathrm{-\; x}}\mathrm{)\; (\; 7\; )}$

N=C in the formula ₄R ₁₄/ C ₃R ₁₀, X=T/ τ,

Fig. 5 (b) is E, △ U _O3, △ U _O3', the T graph of relation is according to (3), (4), (5) formula, △ U _O3Value can just can bear, so the ordinate of Fig. 5 (b) is represented absolute value.

As shown in Figure 2, △ U _O3' be the incoming level of " positive negative pulse stuffing detection " circuit, when its peak value is │ 0.3V │ (slightly change in the practicality), just can cause the protector action, by Fig. 5 b as can be known, I causes the △ U of action _O3ZBe setting value.

Have: △ U _O3Z=△ U ' _O3/ 0.496=│ 0.6V │.

So, the shock current (footnote adds d) that can cause action is expressed as follows:

I _HdC=△ U _O3Z/ KCos φ _C(formula 8)

I _HdA=△ U _O3Z/ KCos(120 °+φ _C) (formula 9)

I _HdB=△ U _O3Z/ KCos(-120+ φ _C) (formula 10)

I _HdA, I _HdB, I _HdCBe respectively A, B, C and can cause the shock current of action, I as can be seen mutually _HdIrrelevant fully with leakage current, this is characteristics of the present utility model places.But I _HdSeparate and φ with shock current _CRelevant, with φ in the formula (8) _CI during=o _HdCBe 1, separate, φ so gets an electric shock _C, I _HdRelation as shown in table 1: (table vides infra)

In the table, because △ U _O3ZTake absolute value, so I _HdAlso should take absolute value; Insensitive phase/sensitivity is meant mutually at same φ _CSituation under, I _HdMaximum electric shock is separate/I _HdMinimum electric shock is separate; I _HdThe sensitive phase of minimum another name mutually, on the contrary be insensitive phase.

About the removing method that differs.As known from Table 1, work as φ _C=± n60 ° of (n=0,1,2,3 ...) time, the I of each phase _HdDifference minimum (2 times).The utility model takes out single phase poaer supply mutually from C and makes baseline signal, U _CDetermine less fixed phase difference is arranged, between them with the C load condition of surveying by the structure and the secondary of power transformer that differs mutually by R ₅, C ₂, R ₆(see that Fig. 3 a) forms the integral correction network, adjusts R in the practicality ₅Can make U ' _CWith C differing mutually is zero.

When nonlinear resistance of human body basic equivalence under the power frequency state so human electric shock, differing of shock current and power supply is minimum, but may have the bigger φ that differs between first and second side of zero sequence current mutual inductor _C'.φ in theory _C' with φ _CCan cancel each other when identical.But in fact can't guarantee the direction that differs identical (for example zero sequence current mutual inductor primary winding reversal connection, the reversal connection of secondary the end of a thread, the transposing of transformer the end of a thread etc.), have only φ _C', φ _CWhen being zero, no matter could in practicality, any situation all meet φ in the table 1 _CIt is zero condition.Through test.φ _C' by zero sequence current mutual inductor secondary side load Z ₂Decision, Z ₂More little then φ _C' also more little.The utility model 1A ₁Electric current---voltage conversion circuit is with I for composition _O2Be transformed into U _O1(I _O2Secondary loop current for zero sequence current mutual inductor).The Z of this circuit ₂Minimum (being connection resistances substantially, about 0.5 Ω) can (5～300mA) make I in very wide scope _o-U _O1Differ very little, I simultaneously _o-U _O1Linearity also fine, its U _O1/ I _oBasic is constant, and measured performance is seen Fig. 6.In addition, this circuit also has significant effect to improving the load current characteristic.

About theoretical operating characteristics and deviation thereof.Make φ _C=φ _CAfter '=0, the utility model has following electric shock performance:

I _HdA=I _HdB=2I _HdC=△ U _O3Z/ K (formula 11)

In following formula, regulate the K value, just can obtain our needed electric shock operating current, for example make I _HdA=I _HdB=15mA, then I _HdC=7.5mA.In the utility model, we are called sensitive phase with C phase (power supply phase), and two are called insensitive phase in addition.Insensitive and sensitive ratio mutually is 2 times in theory, in fact slightly change about 2 times, but practicality is not hindered.

Can make the on all four method of three-phase electric shock operating current.The utility model can also use three groups of identical IA ₂, 2A ₃, 1A _3,4Circuit and every group insert A, B respectively, C three-phase reference circuit replaces set of circuits shown in Figure 2, can make three-phase electric shock operating current (see figure 7) in full accord.

The key technical indexes of the present utility model is:

(1), load current: 100A, 150A, 250A(cooperate corresponding zero sequence current mutual inductor),

Overload capability＞＞5 times not malfunction of rated value,

(2), over the ground operating current gets an electric shock: leakage current is no more than 70% electric leakage setting value, when leakage current can be arbitrary phase,

C phase: 7.5 ^{+ 10} _-30%mA～30mA ± 5%

A, B phase: 15 ^{+ 10} _-30%mA～60mA ^{+ 5} _-10%

By W ₁Potentiometer is regulated continuously.

(3), Leaked Current of Line to Ground operating current 75 ± 10%mA～300 ± 10mA(is equally by W ₁Potentiometer and the interlock of electric shock operating current are regulated).

(4), get an electric shock operate time over the ground: during sensitive locations, when the actual act electric current is 30mA,＜0.1 second.

(5), the actual electric shock operating current the during leakage current of different amplitudes and phase place is seen Fig. 8.

The phase-sensitive rectifier circuit that the utility model adopts polarity inverting amplifier to constitute has solved there is operating dead zone in former Pulse Electric flow pattern protector because of the influence that is subjected to leakage current disadvantage effectively, make the action of getting an electric shock irrelevant with leakage current, again with easy method eliminated the zero sequence current mutual inductor output signal and and reference voltage between differ, also can further adopt identical phase depending on rectification, the differential of three covers, the positive negative pulse stuffing testing circuit also proposes the three-phase baseline signal respectively, makes three-phase electric shock operating current in full accord.Zero sequence current mutual inductor of the present utility model and protector are convenient to the installation and the operation of described protector for dividing body structure.The utility model is used for the low pressure electrical shock protection; owing to can will get an electric shock and electric leakage separate fully, so that special adaptation hinders extremely is low, China's rural low voltage network protection usefulness that the three-phase imbalance leakage current is big; can keep putting into operation on the big circuit of leakage current, electrical shock protection simultaneously be highly sensitive.And it is simple and reasonable for structure, with low cost.

Attached picture explanation: Fig. 1 is a pictorial diagram of the present utility model.Wherein:

The 1-zero sequence current mutual inductor

2-L ₁(load circuit) through wires hole

The line of 3-zero sequence current mutual inductor and main frame

4-touches, the residual operating current release handle

5-action indication luminous tube

The 6-test button

7-terminal board

The 8-terminals

The 9-reset button

10-power supply indication luminous tube 11-main frame

Fig. 2 is a theory diagram of the present utility model.

Fig. 3 is that (Fig. 3 a) and working waveform figure (Fig. 3 b) for phase-sensitive rectifier circuit figure of the present utility model.

Fig. 4 is the polar plot when respectively mutually electric shock taking place, and polar plot was respectively (a) and (b), (c) when C, A, B respectively got an electric shock mutually.

Fig. 5 is that (Fig. 5 a) and output waveform (Fig. 5 b) for differential circuit.

Fig. 6 points out I _o-U _O1Between relation.

Fig. 7 makes the on all four theory diagram of three-phase electric shock operating current.

Fig. 8 is actual measurement I _Hd, I _L, φ _LRelation curve.

Fig. 9 is a phase depending on rectification Pulse Electric flow pattern protector schematic diagram.

Claims (1)

1, a kind of phase depending on rectification formula Pulse Electric flow pattern protector that can prevent personal electric shock injures and deaths, it comprises that central part has the current transformer (1) of through wires hole (2), main frame (11) and main frame internal work circuit, line (3) is communicated with main frame (11) with instrument transformer (1), feature of the present utility model is, have on the main frame (11) and be installed in touching residual operating current regulating handle (4) and being installed in the test button (6) of end face of end face central part, reset button (9), action luminous tube (5) and power supply indicator tube (10) are arranged between button (6) and (9), there are terminals (8) and terminal board (7) in the bottom of main frame (11), and what described main frame (11) internal work circuit comprised and zero-sequence transformer (1) is joined makes the zero-sequence transformer secondary load minimum to improve its non-linear and basic current-voltage conversion circuit 1A1 that eliminates the effect of phase distortion, the phase-sensitive rectifier circuit 1A2 that constitutes by polarity inverting amplifier that joins with 1A1, reduce the not filtering and the DC amplifying circuit 2A3 of the gap of homophase electric shock operating current with 1A2 joins, be connected on the integral correction lattice network that elimination differs in the reference voltage loop.

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