RU2688144C1 - Method of adaptive single-phase automatic reconnection of power transmission lines - Google Patents

Abstract

FIELD: electrical equipment.

SUBSTANCE: field of application: electrical equipment. According to the method of adaptive single-phase automatic reconnection of power transmission lines, two-sided disconnection of the damaged phase is performed, characterized by that a one-sided activation of the emergency phase on the side of the intermediate system is carried out for short-term within 0.1 s, measuring current value of current of this phase at connected end and comparing with setpoint, if current is higher than setpoint, then short or arc short-circuit is fixed on phase and then command is given to disconnect line, otherwise there is no phase closure, and it is successfully switched on with other side.

EFFECT: high reliability of single-phase automatic reconnection of power transmission lines with any number of shunt reactors (SHR) on the line, as well as reliable identification of arc damage, which can not be detected on the double-side disconnected emergency phase.

1 cl, 1 dwg

Description

The invention relates to electrical engineering, in particular, to automation of electric power systems and can be used to ensure high reliability of adaptive single-phase automatic reclosing (AOAPO) power lines equipped with any number of shunt reactors (SR), including the case of their absence.

The known method AOAPV transmission lines (USSR Author's Certificate No. 792398, Cl. Н02Н 3/06, 1979), based on the measurement of voltage modules at the ends of the disconnected line phase and comparing them with the given settings. When both voltages exceed the specified settings, this means the disappearance of the circuit.

The disadvantage of this method is the low reliability of AOAPO in cases where the line is not equipped with SR or is equipped with an incomplete number. In addition, when implementing the method requires the organization of a high-frequency communication channel between the semi-sets of the device installed at the ends of the line.

Also known method AOAPV transmission lines (USSR Copyright Certificate No. 869537, CL ННН 3/06, 1980), which is the prototype of the present invention and consists in measuring and comparing the set values of the voltage on the disconnected line phase and the effective value of the symmetrical component of the line current. If the values of the current component are below the setpoint, and the voltage values are higher than the setpoint, then it fixes the disappearance of the circuit.

However, this method does not eliminate the rather low reliability of the AOADO in those cases when the line is not equipped with SR or is equipped with an incomplete number.

It is known that the effective value of the symmetric component of the line currents is a unique function of the angle of divergence between the vectors of equivalent emf of adjacent systems. At angles greater than a certain limiting value, the voltage on the disconnected phase in the presence of a remote circuit on it can be comparable with the restoring voltage and even exceed it. Thus, in the prototype, the range of AOAPO is limited by the boundary angle. The measured effective value of the symmetrical component of the line currents allows the implementation of AOAPO not to go beyond this range. But in these cases, when the line is not equipped with an SR or is equipped with an incomplete number, the value of the boundary angle can be 30-40 °, while in real power transmission, taking into account possible swings of adjacent systems, the range boundary of the AOAPO should reach 110-120 °.

The task (technical result) of the present invention is to create a fairly high reliability of AOAPO transmission lines, equipped with any number of SR, including the case of their absence.

The task is achieved by the fact that in a known method, after two-sided disconnection of the damaged phase of the line, the emergency phase is switched on for a short time within 0.1 sec from the intermediate system, the effective value of the current of this phase at the included end is measured and compared with the set value if the current is higher setting, then the phase is fixed short or arc circuit and then give the command to turn off the line, otherwise the circuit on the phase is absent, and it is successfully included on the other side us

The drawing shows a structural diagram of the device that implements the proposed method.

The device contains the phases of lines 1 and 2, connected to systems 3 and 4 with the help of switches 5 and 6, for any number of SR 7 on the lines, including the case of the absence of SR. Damage may occur at any of phases 1 or 2 8.

The method is as follows. Two-way disabled emergency phase 1 or 2 can be in one of three states. When damage resistance R 8 = R _{AB IKP} <10 ohms holds unremovable single-phase short circuit (IKP), with R = R _{AB d>} 200 ohm arcing fault occurs and R _AB → ∞ damage on the offline phase. However, in the latter case there is no complete guarantee that the AOAPO will be successful. Indeed, in case of overlapping of one of the phases in the span of the tree, the arc will go out after two-way shutdown of the emergency phase, and the strength of the gap will be restored, but the subsequent switching on of the phase will cause the gap to re-overlap, because there is a hidden weak spot on the line that cannot be detected when the switch is off emergency phase. The two-sided disconnected emergency phase 1 is turned on unilaterally from the intermediate system 4 by means of the switch 5, the effective value of the current of this phase at the switched end I _{av is} measured and compared with the preset setting I _set. If the measured current is higher than the setting I _av > I _set , then there is a short or arc fault in the phase, and a command is given to turn off the line. Otherwise, a short circuit in the phase is absent, and it is successfully switched on from the other side.

The preset current setting is selected from the condition of detuning from the highest current I _max determined at the one-sided end of the phase in the absence of damage.

I _set ≥I _max ⋅K _n ⋅K _h ,

K _n = 1,1 - reliability factor

K _h = 1.25 - coefficient of sensitivity.

For extra high voltage lines in the interval of lengths of 100-500 km, depending on the number of SRs on the line, the setpoint is no more than 250 A for 500 kV lines and 550 A for 750 kV lines, while the possible range of currents at the included end of the emergency phase in the presence of OKZ or arc is not less than 800 A for 500 kV lines and 1200 A for 750 kV lines, which is more than 3 times greater than the setpoint for 500 kV lines and more than 2 times the setpoint for 750 kV lines. Thus, there is a reliable guarantee of damage identification.

The inclusion of the intermediate system 4, the power of which, as a rule, is significantly less than the power of adjacent systems 3, is characterized by low short-circuit currents if the OKZ remains in phase and therefore does not pose a danger to the equipment.

The technical result is to ensure high reliability of AOAPO transmission lines for any number of SR on the line, including the case of the absence of SR. In addition, the method ensures reliable identification of arc damage that cannot be detected on the two-way disabled emergency phase.

Claims (1)

The method of adaptive single-phase automatic reclosing of power lines, in which a two-way disconnection of the damaged phase is carried out, characterized in that a one-sided activation of the emergency phase from the intermediate system for a short time within 0.1 s setpoint, if the current is higher than the setpoint, then a short or arc circuit is fixed at the phase and then a command is given to turn off the line, otherwise the circuit Phase is absent, and it is successfully turned on from the other side.

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