JPH0250724U - - Google Patents

Description

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of an embodiment of this invention, Figure 2 is a block diagram showing the specific configuration of the main parts of Figure 1, and Figure 3 is an example of a conventional reactive power compensator. FIG. 2 is a block diagram showing the configuration. 1... Power system, 2... Load, 3... Slow phase circuit, 3A... Reactor, 3B, 3C... Thyristor, 4... Phase advance capacitor, 5... Series resonant circuit, 6... Reactive current detection Circuit, 7... Firing angle calculation circuit, 8... Inverter circuit, 9... Harmonic calculation circuit, 10... Inverter command value calculation circuit.

Amendment 1.3.3 The scope of claims for utility model registration is amended as follows.

[Claims for Utility Model Registration] (1) A slow-phase circuit for reactive current compensation consisting of a series circuit of a reactor and a thyristor, connected in parallel to a load supplied with power from the power system, and a reactive circuit connected in parallel to this slow-phase circuit. A phase advance capacitor for current compensation, and a phase advance capacitor whose resonance frequency matches the power system fundamental wave frequency and which is inserted between the neutral point side terminal of the phase advance capacitor and the power system neutral point, are injected. A reactive power compensator comprising a series resonant circuit constituting a circuit, and an inverter circuit for harmonic compensation whose output end is connected to a connection point between the phase advancing capacitor and the series resonant circuit. (2) A phase delay circuit for reactive current compensation consisting of a series circuit of a reactor and a thyristor connected in parallel to the load supplied from the power system, and a phase advance capacitor for reactive current compensation connected in parallel to this phase delay circuit. , a series resonant circuit whose resonance frequency matches the power system fundamental frequency , is inserted between the neutral point side terminal of the phase advance capacitor and the power system neutral point, and constitutes an injection circuit with the phase advance capacitor ; a reactive current detection circuit that detects a reactive current component in a load current flowing from the power system to a load; and a compensation reactive current that cancels out the reactive current component in the load current detected by the reactive current detection circuit. and a firing angle calculation circuit that calculates a firing angle of the thyristor to flow as a composite current of the phase advance capacitor and conducts the thyristor at the calculated firing angle, and a firing angle calculation circuit that connects the phase advance capacitor and the series resonant circuit. an inverter circuit for high frequency compensation whose output end is connected to the connection point; and a harmonic calculation for calculating harmonic current components that are included in the current of the phase lag circuit and whose content differs depending on the firing angle of the thyristor. A command value that determines the on/off timing of the switching element of the inverter circuit is calculated in accordance with the harmonic current component in the current of the slow phase circuit calculated by the harmonic calculation circuit, and the command value is calculated. an inverter command value that cancels harmonic current components in the current of the slow phase circuit with compensation harmonic current injected from the inverter circuit into the power system by controlling on/off switching elements of the inverter circuit according to the result; A reactive power compensator equipped with an arithmetic circuit.

Claims (1)

[Scope of utility model registration request] A phase delay circuit consisting of a series circuit of a reactor and a thyristor is connected in parallel to a load supplied with power from the power system, and a phase advance capacitor is connected in parallel to this phase delay circuit, and the resonant frequency matches the power system fundamental frequency. A series resonant circuit inserted between the neutral point side terminal of the phase advance capacitor and the power grid neutral point,
a reactive current detection circuit that detects a reactive current component in a load current flowing from the power system to a load; and a compensation reactive current that cancels out the reactive current component in the load current detected by the reactive current detection circuit. and a firing angle calculation circuit that calculates the firing angle of the thyristor to flow as a composite current of the phase advance capacitor and conducts the thyristor at the calculated firing angle; an inverter circuit that injects a compensation harmonic current from a connection point into the power system; and a harmonic that is included in the current of the phase-lag circuit and calculates a harmonic current component whose content differs depending on the firing angle of the thyristor. A calculation circuit calculates a command value that determines the on/off timing of the switching element of the inverter circuit in accordance with the harmonic current component in the current of the slow phase circuit calculated by the harmonic calculation circuit, and calculates the command value. an inverter command for canceling a harmonic current component in the current of the slow phase circuit with a compensation harmonic current injected from the inverter circuit into the power system by controlling on/off switching elements of the inverter circuit according to a calculation result; A reactive power compensator equipped with a value calculation circuit.