CN201229849Y

CN201229849Y - External integration type Rogowski coil current mutual inductor

Info

Publication number: CN201229849Y
Application number: CNU2008200720125U
Authority: CN
Inventors: 石宝山; 王乐仁; 曹凤田; 孙桂新; 王珏昕; 王伯时; 杨伟光
Original assignee: Electric Power Research Institute Of Jilin Electric Power Co
Current assignee: Electric Power Research Institute Of Jilin Electric Power Co; State Grid Corp of China SGCC; Electric Power Research Institute of State Grid Jilin Electric Power Co Ltd
Priority date: 2008-06-20
Filing date: 2008-06-20
Publication date: 2009-04-29
Anticipated expiration: 2018-06-20

Abstract

The utility model relates to an external integration Rogowski coil current transformer. A Rogowski coil is wound on a circular non-magnetic framework evenly in a circumference; a primary current conductor goes through an axis of a circular coil; a reactor with appropriate inductance and a secondary load resistor with appropriate inductance are serially connected between two lead-out terminals of the coil; an input resistor of a secondary electronic equipment circuit is also included in the load resistor; compensation capacitors are parallelly connected with both ends of the secondary load resistor to compensate for the phase of the voltage on both ends of the resistor, and meet the error requirements of the protective electronic current transformer by the micro-adjustment to the parameters of the load resistor and the compensation capacitor. The current transformer has the advantages that the structure is novel, the restriction that the internal integration Rogowski coil current transformer is used for large current is overcome, so that the current transformer can be used for the fault current protection to a high-voltage power grid, and usually the current reaches 10kA to 100Ka.

Description

A kind of outer integration type rogowski coil current transformer

Technical field

The utility model relates to current transformer, especially uses the electronic current mutual inductor of rogowski coil, belongs to the electric power mutual-inductor technical field.

Background technology

110kV and above power network make Current Transformer carry out circuit and equipment protection in a large number at present.Traditional current transformer is pressed GB 1208 " current transformer " and is made, and by iron core and once constituting with secondary winding on the iron core, by electromagnetic induction principle work, the secondary rated current is 5A and 1A.Electronic current mutual inductor is pressed GB/T 20840.8 " instrument transformer the 8th part: electronic current mutual inductor " and is made; its secondary analog output voltage rated value is no more than 4V; the secondary rated voltage is generally got 225mV when being used to protect, can be directly as the input signal of secondary electron device line.Integration type and inner product fraction were two kinds outside the electronic current mutual inductor that adopts rogowski coil and have homophase output had on using.The rogowski coil of outer integration type current transformer has enough big resistance, by the capacitance integral circuit that is connected on the coil outside electrorheological of secondary circuit is changed into and the synchronous voltage of primary current, the rogowski coil of inner product fraction current transformer has enough big self-induction, can obtain and the synchronous voltage of primary current on the little secondary load resistance of resistance.The advantage of rogowski coil current transformer is can be because of flip-flop in the primary current and the excessive generation magnetic saturation of first short circuit electric current, and this is for the transient protection advantageous particularly of circuit.But outer integration type rogowski coil current transformer need use electron-amplifier, has reduced the reliability of current transformer; And the rogowski coil current transformer that adopts the integrates phase shift is when being used for big electric current, because the self-induction of coil is little, the phase shift error is very big, can not satisfy the use accuracy requirement, and the scope of application is liked restriction.

Summary of the invention

The utility model provides a kind of outer integration type rogowski coil current transformer, accuracy with the big electric current rogowski coil current transformer that improves the integrates phase shift, avoid using electron-amplifier simultaneously, this instrument transformer belongs to the integrates phase shift on principle, but be not subjected to the self-induction of loop quantitative limitation, higher reliability arranged than the outer integration rogowski coil current transformer that uses electron-amplifier.

The technical solution adopted in the utility model is: series connection inserts reactor and secondary load resistance between two outlet terminals of rogowski coil, the phase compensation capacitor in parallel at these secondary load resistance two ends.

Rogowski coil is wound on annulus in the circumference uniform distribution mode in the utility model does not have on the magnetic skeleton, and the primary current conductor passes along this Circumferential coils axis.

The electrical principle of the technical program can be used the equivalent electric circuit explanation of Fig. 2.Primary current is among the figure

The mutual inductance of rogowski coil is M, and self-induction is L ₀, equivalent loss resistance is R under the 50Hz ₀, the secondary induced potential is

{\overset{\cdot}{E}}_{2} = - jωM {\overset{\cdot}{I}}_{1},

The inductance value of reactor is L _m, equivalent loss resistance is R under the 50Hz _m, the resistance of secondary load resistance is R _b, the capacitance of compensation condenser is C _b, secondary voltage is output as:

{\overset{\cdot}{U}}_{2} = \frac{jωM {\overset{\cdot}{I}}_{1}}{R_{0} + jω L_{0} + jω L_{m} + R_{m} + \frac{R_{b}}{1 + jω R_{b} C_{b}}} \cdot \frac{R_{b}}{1 + jω R_{b} C_{b}}

= \frac{jωM R_{b} {\overset{\cdot}{I}}_{1}}{R_{b} + R_{0} + R_{m} - ω^{2} (L_{0} + L_{m}) R_{b} C_{b} + jω (L_{0} + L_{m} + R_{0} R_{b} C_{b} + R_{m} R_{b} C_{b})}

Work as R _b+ R ₀+ R _m=ω ²(L ₀+ L _m) R _bC _bThe time, phase place obtains full remuneration, at this moment has:

{\overset{\cdot}{U}}_{2} = \frac{{MR}_{b} {\overset{\cdot}{I}}_{1}}{L_{0} + L_{m} + R_{0} R_{b} C_{b} + R_{m} R_{b} C_{b}}

The beneficial effects of the utility model are novel structures, have overcome the restriction that inner product fraction rogowski coil current transformer is used for big electric current, make it can be used for the fault-current protection of high-voltage fence, and common this electric current reaches 10kA～100kA.

Description of drawings

Fig. 1 is a circuit diagram of the present utility model.

Fig. 2 is an equivalent circuit diagram of the present utility model.

Among the figure: 1. primary current conductor, 2. annulus does not have the magnetic skeleton, 3. rogowski coil, 4. reactor, 5. secondary load resistance, 6. secondary voltage output, 7. phase compensation capacitor.

Embodiment

In Fig. 1, rogowski coil 3 is wound on annulus in the circumference uniform distribution mode not to be had on the magnetic skeleton 2, primary current conductor 1 passes along the Circumferential coils axis, series connection inserts reactor 4 and secondary load resistance 5 between two outlet terminals of coil, at this secondary load resistance two ends parallel capacitor 7, its effect is the phase place of compensating resistance both end voltage, makes the voltage-phase of secondary voltage output 6 approaching consistent with the primary current phase place.

In the embodiment of Fig. 1; primary current conductor 1 flows through power current 2500A; the structure of rogowski coil 2 is that circumference uniform distribution is suitable around 2500 circles on the plastic hoop of φ 495 * 420 * 70; D.C. resistance 25 Ω of winding; induced voltage 4.6V; the coil secondary circuit seals in the reactor 4 of reactance value 2000 Ω and the secondary load resistance 5 of resistance value 100 Ω; the input resistance of secondary electron device line is also included within the load resistance 5; the equivalent loss resistance of reactor 4 under 50Hz is 60 Ω; the capacitor 7 of resistor two ends one 3 μ F in parallel; on secondary voltage output 6, obtain exporting near the voltage of homophase of about 225mV, again by 0.5 grade of protection electronic type current transformer error requirement is satisfied in the parameter fine setting of resistance 5 and electric capacity 7 at last with primary current.

Claims

1, a kind of outer integration type rogowski coil current transformer is characterized in that: series connection inserts reactor and secondary load resistance between two outlet terminals of rogowski coil, the phase compensation capacitor in parallel at these secondary load resistance two ends.

2, outer integration type rogowski coil current transformer according to claim 1, it is characterized in that: rogowski coil is wound on annulus in the circumference uniform distribution mode not to be had on the magnetic skeleton, and the primary current conductor passes along this Circumferential coils axis.