RU2160193C2 - Ac traction power system short-circuit fault distance indicator - Google Patents

Abstract

FIELD: electrified transport. SUBSTANCE: proposed indicator has substation voltage transmitter, contact system feeder current transmitter, recorder unit, substation supply circuit branch current transmitter and multifunctional converters. Device provides determination of distance to short-circuit fault depending on current-to- voltage phase angle, taking into account shunting ground effect and inductive impedance on a length of 1 km according to relative inductive coupling of converging track contact systems, contact system of one track and track circuit. EFFECT: improved accuracy of measurement owing to taking into account shunting ground effect and relative influence of adjacent tracks and arc resistance. 3 cl, 1 dwg

Description

 The invention relates to electrified transport and can be used in traction power supply systems to determine the distance of a short circuit in an AC traction network.

где U_A - напряжение контактной сети; I'₁ - ток фидера контактной сети с коротким замыканием (ток поврежденного фидера контактной сети); φ₁- фазовый угол между этими напряжением и током.A device is known for determining the location of damage to a traction network of an electrified railway, comprising a voltage sensor, a current sensor of a damaged feeder of a contact network, a multifunction converter and a recorder (author's certificate. 158328 SU, class 21 C, 68/50; IPC H 02 D. Device to determine the location of a short circuit in the contact network / E.P. Figurnov (SU). N 798020 / 24-7; decl. 08/10/1962; publ. 10/19/1963, bull. N 21). This device calculates the magnitude of the inductive component of the impedance of the short circuit loop X _SCC by the formula:

where U _A is the voltage of the contact network; I ' ₁ - current of the feeder of the contact network with a short circuit (current of the damaged feeder of the contact network); φ ₁ is the phase angle between these voltages and currents.

By the value of X _SCR judge the remoteness of the short circuit.

A disadvantage of the known device is the low accuracy due to the fact that between the calculated value of X _SCR and the distance of the short circuit there is no direct and unambiguous relationship due to factors such as the shunting effect of the earth on the resistance of the rail track, the effect of mutual inductive coupling between contact networks of different paths on their resistance, the presence of an arc short circuit or transition resistance in case of two-way power supply of the contact network of the inter-substation zone.

 The aim of the invention (technical result) is to increase the accuracy of determining the distance from the traction substation short circuit in the traction network.

The inventive device comprises a voltage sensor U _A , a current sensor of a controlled feeder of a contact network I ' ₁ , a current sensor of a supply arm of a substation I _A , first, second, third and fourth multifunction converters, a multiplier, a distance adjuster from the traction substation to the sectioning station or to an adjacent substation, if there is no post, a functional unit designed to generate the coefficient ν _A , taking into account the shunting effect of the earth, and a registration unit.

где φ₁- фазовый угол между напряжением U_A и током I'₁, δ- дополнительный фазовый угол, задаваемый четвертым многофункциональным преобразователем. Второй многофункциональный преобразователь выполнен с возможностью реализации функции I_A(x_вс+ν_Ax_р,m), где x_вс- известное индуктивное сопротивление взаимной индуктивной связи контактных сетей смежных путей на длине 1 км, x_p,m- известное индуктивное сопротивление рельсовой линии на длине 1 км. Третий многофункциональный преобразователь выполнен с возможностью реализации функции

где l_к - удаленность короткого замыкания, т.е. расстояние от подстанции до точки короткого замыкания тяговой сети.The first multifunction converter is configured to implement a function

where φ ₁ is the phase angle between voltage U _A and current I ' ₁ , δ is the additional phase angle specified by the fourth multifunction converter. The second multifunctional converter is configured to implement the function I _A (x _vs + ν _A x _{p, m} ), where x _sun is the known inductive resistance of the mutual inductive coupling of contact networks of adjacent paths over a length of 1 km, x _{p, m} is the known inductive resistance of the rail lines at a length of 1 km. The third multifunction converter is configured to implement a function

where l _to is the distance of the short circuit, i.e. distance from the substation to the short circuit point of the traction network.

 The fourth multifunction converter is made in the form of a nonlinear converter that realizes the dependence of the angle δ on the ratio of the distance of the short circuit to the distance to the sectioning station or to an adjacent substation if there is no station.

The multiplier is configured to implement function I $\genfrac{}{}{0ex}{}{\text{′}}{\text{1}}$ (x _{c, 1} -x _sun ), where x _{c, 1} is the known inductive reactance of 1 km of the contact network.

In the distance controller, the value of the distance l ₁ from the substation to the sectioning station or to the adjacent substation, if there is no station, is set.

The functional unit is made in the form of a nonlinear converter that implements the dependence of the coefficient ν _A on the distance of the short circuit l _to .

The output of the voltage sensor U _{A is} connected to the first inputs of the first and third multifunction converters. The output of the current sensor I ' _{1 is} connected to the second input of the first multifunction converter, the output of which is connected to the second input of the third multifunction converter, and through the multiplier to the third input of the third multifunction converter. The output of the current sensor I _{A is} connected to the first input of the second multifunction converter, the output of which is connected to the fourth input of the third multifunction converter, the output of which is connected to the registration unit, to the input of the function block, the output of which is connected to the second input of the second multifunction converter and to the first input of the fourth multifunction transducer. The second input of the latter is connected to the said distance switch, and the output of the fourth multifunction converter is connected to the third input of the first multifunction converter.

 New is the introduction of the current sensor of the arm of the power substation, the first, second, third and fourth multifunction converters with the possibility of implementing the above functions, a multiplier, a distance adjuster and a functional unit, as well as communication between the elements. This ensures that the shunting effect of the earth, the mutual inductive effect of contact networks of adjacent paths, the presence of an arc in the place of a short circuit are taken into account, which increases the accuracy of determining the distance of a short circuit. Obtaining a technical result is ensured by the combination of all the essential features listed.

The drawing shows a structural diagram of the proposed device, it contains: sensor 1 voltage U _A on the substation buses, sensor 2 current I ' _{1 of the} controlled feeder of the contact network, sensor 3 current I _{A of the} arm of the power substation, the first multifunction converter 4, multiplier 5, the second multifunction converter 6, a third multifunction converter 7, a recording unit 8, a distance adjuster 9, a fourth multifunction converter 10, a function block 11.

 Elements 1,2,8 are known from the prototype, the remaining blocks are new.

The current sensor I _{A of the} power arm of the traction substation can be made in the form of a current transformer included in the phase of the transformer that powers this arm. More accurate results may be obtained, if the sensor current I _A to use the same type of current transformers catenary feeder all paths of the power arm, the secondary windings are connected in parallel (at the geometrical sum of the currents of feeders).

Elements 4, 5, 6, 7 perform the operations of addition, subtraction, multiplication, division and trigonometric functions and can be performed using analog or digital technology. Elements 10 and 11 are non-linear functional converters of one variable l _to and can also be performed on the basis of analog or digital technology. When using analog technology, the setter 9 can be made in the form of a potentiometer or operational amplifier with adjustable feedback, and when using digital technology, in the form of a code encoder.

I_A(x_вс+ν_Ax_р,m). Значения этих величин поступают на входы элемента 7, на выходе которого реализуется зависимость (1) в виде величины, пропорциональной удаленности короткого замыкания l_к. Значение этой величины поступает на входы элементов 10 и 11, на выходе которых формируются соответственно значения угла δ и коэффициента ν_A, зависящие от величины l_к.The device operates as follows. If a short circuit occurs in the contact network, a command is issued to turn the device on. In this case, element 1 measures and fixes the voltage U _A on the substation buses, element 2 measures and fixes the current I ' _{1 of the} controlled feeder of the contact network with a short circuit, element 3 measures and fixes the current I _{A of} the supply arm (phase) of the substation from which The damaged contact network receives power. The output signals of these elements, proportional to the corresponding measured values, go to elements 4, 5, 6, at the output of which values proportional to the dependencies are realized

I _A (x _sun + ν _A x _{p, m} ). The values of these quantities are supplied to the inputs of element 7, at the output of which dependence (1) is realized in the form of a value proportional to the short circuit distance l _to . The value of this quantity is supplied to the inputs of elements 10 and 11, at the output of which values of the angle δ and coefficient ν _A , respectively, are formed, depending on the value of l _k .

The output of element 10 is included in the feedback circuit of the first multifunction converter, and the output of element 11 is included in the feedback circuit of the second multifunction converter. Due to this, at the output of the third multifunction converter in the quantity l _k , the nonlinear effects of leakage currents from the rails to the ground and arcs in the place of a short circuit depending on it are taken into account. The obtained value of the distance l _k is fixed in block 8.

 The proposed device allows more accurately than the prototype and analogues to determine the distance from the substation of the short circuit in the traction network, since it additionally takes into account the nonlinear dependences of the shunting effect of the earth on the rail circuit, the mutual inductive coupling of contact networks of different paths and the influence of the arc with two-way power.

Claims (3)

1. The indicator of the remoteness of a short circuit in the traction AC network, containing a voltage sensor U _A on the substation buses, a current sensor I ' _{1 of the} controlled feeder of the contact network, a registration unit, characterized in that it also includes a current sensor I _{A of the} power supply arm of the traction substation , the first, second, third and fourth multifunction converters, a multiplier, a distance adjuster from a traction substation to a sectioning station or to an adjacent substation, if there is no station, a function block d to form the coefficient ν _A , which takes into account the shunting effect of the earth, and the output of the voltage sensor U _{A is} connected to the first inputs of the first and third multifunction converters, the output of the current sensor I ' _{1 is} connected to the second input of the first multifunction converter, the output of which is connected to the second input of the third multifunction converter, and through the multiplier to the third input of the third multifunction converter, the output of the current sensor I _{A is} connected to the first input of the second multifunction a common converter, the output of which is connected to the fourth input of the third multifunction converter, the output of which is connected to the registration unit, to the input of the function block, the output of which is connected to the second input of the second multifunction converter, and to the first input of the fourth multifunction converter, to the second input of which distance, and the output is connected to the third input of the first multifunction converter, while the multiplier is made with the ability to implement a function

where x _{c, 1} is the known inductive reactance of 1 km of the contact network, and x _sun is the known inductive resistance of mutual inductive coupling of the contact networks of different paths over a length of 1 km, the first multifunction converter is configured to implement the function

where φ _{1 ′} is the phase angle between the current and voltage U _A , and δ is the additional phase angle specified by the fourth multifunction converter, the second multifunction converter is configured to implement the function I _A (x _vs + ν _A x _{p, m} ), where x _{p, m} is the known inductive resistance of the rail line over a length of 1 km, and the third multifunction converter is configured to implement the function

where l _k is the distance of the short circuit. 2. The device according to p. 1, characterized in that the fourth multifunction converter is made in the form of a nonlinear converter that realizes the dependence of the angle δ on the ratio of the distance of the short circuit l _k to the distance to the section station or to an adjacent substation if there is no station. 3. The device according to claim 1, characterized in that the functional unit is made in the form of a nonlinear converter that implements the dependence of the coefficient ν _A on the distance from the short circuit location l _k .